English Grammar Basics

A brief overview of English grammar and how it is used in VoiceBox.

WARNING: For grammar nerds only

VoiceBox builds a sentence one word at a time. After each tap it shows only the words that can come next in correct English, and it puts each word in the right form for you: she is followed by wants, not want, and these by shoes, not shoe.

This guide explains the English grammar behind that, so that you can add and edit words in Settings ▸ Custom Dictionary and have them behave as you expect. A word’s part of speech, its forms and its features decide where it can appear in a sentence.

You do not need to understand this page to use VoiceBox successfully, infact most native english speakers do know know grammar but they can speak english perfectly well, however some basic understandig is required when adding custom words for them to behave as expected.

Contents

  1. Adding a word
  2. Parts of speech
  3. Basic sentence structure
  4. Plurals
  5. Agreement
  6. Verb forms and tense
  7. Other features of English
  8. Known limits
  9. Quick reference: forms and features

1. Adding a word

In Settings ▸ Custom Dictionary, tap +. A word has four parts:

Part What it is for
Lexeme The word itself, in its plain form: biscuit, not biscuits; run, not ran.
Parts of Speech What kind of word it is (noun, verb, …). Choose more than one if the word plays more than one role: drink is a noun and a verb.
Forms (optional) Spellings the app cannot work out for itself: feet for foot, ran for run. See Plurals and Verb forms.
Features (optional) Facts about how the word behaves: whether a noun can be counted, whether a verb takes an object, and so on. Add Feature only lists the features that apply to the parts of speech you chose.

Weight (0 to 1) sets how high the word sorts among others of its kind. It does not change the grammar.

A new word is switched on straight away. If it never shows up, the usual reason is that the grammar has no place for it at that point in the sentence, often because a feature is missing. For example, a noun with no Countability cannot follow a or the.

Nouns get one default: a new noun is marked Countability: countable. Change it to uncountable for words like water, music or help.

2. Parts of speech

The editor shows each part of speech as a short code. The word grid shows the full name and a colour (the Modified Fitzgerald Key).

Code Name Colour Examples
NOUN Noun orange cake, doctor, foot, water
PROPN Name (proper noun) orange Christmas, Easter, people’s names
VERB Verb green eat, want, go, feel
AUX Auxiliary (helping verb) green be, do, have
MODAL Modal green can, will, would, should, may, must
ADJ Adjective blue happy, cold, big, comfortable
ADV Adverb brown now, here, very, always, not
PRON Pronoun yellow I, you, me, myself, mine, something
POSS Possessive yellow my, your, his, her, our, their
ADP Preposition pink in, on, at, to, with, after
INTJ Interjection pink yes, no, please, thank you, hello
WH Question word purple what, where, when, why, how, who, which
DET Determiner grey the, a, some, this, these, all, no
PUNCT Punctuation grey . ? 's

Nouns (NOUN)

A noun names a thing, person, place or idea. Its most important feature is Countability:

Some nouns are both (fish, cake: a cake, some cake). Choose both values.

A countable noun on its own in the singular is not correct English (I want biscuit), so VoiceBox offers only the plural there (I want biscuits) until you choose a word such as a, the or my.

Other noun features:

Feature Use it for
Number: plural A noun that only exists in the plural: trousers, pyjamas, clothes. Spell both forms the same (see Plurals).
Bare Locative A place that follows at, in or to with no the: at home, in bed, to church.
Indefinite Article A word whose first sound doesn’t match its first letter: an hour, a university. See a and an.
Semantic Category: time / weekday A time word (yesterday, tonight), or a day name that follows on (on Wednesday, on Mondays).
Tense Which tenses a time word fits. See Time words.
Time With Which of last, next and this the noun can follow: last night, this morning, next week.

Names (PROPN)

Names of people, places and events: Christmas, Sam, Tesco. A name takes no determiner and counts as one person or thing (Sam is here). Only a name can take the possessive 's: Sam’s shoes. The editor capitalises nothing for you, so type the name as it should appear.

Verbs (VERB)

A verb is an action or state: eat, sleep, feel, want. What may follow a verb depends on its features, so this is the part of speech where features matter most.

Transitivity — what follows the verb. A verb can have several.

Value Meaning Example
intransitive Nothing has to follow I sleep, she went home
transitive Takes an object I want tea, help me
ditransitive Takes two objects give him the book, give the book to him
clause Takes a whole sentence I know (that) you are tired
activity Only go: followed by an activity go walking
causative Can’t stand without an object and a verb let me go (not let me)

Verb Subcategory — special patterns. A verb can have several.

Value Meaning Example
linking Followed by a description, not an object (see Takes Predicate) I feel sad, you look tired
infinitive Followed by to + verb I want to eat, I need to go
gerund Followed by an -ing verb I stopped coughing, I enjoy eating
object-infinitive Someone, then to + verb I asked her to wait, I was told to rest
resultative Someone or something, then an adjective it makes me sad, I find this hard
causative Someone, then a plain verb it makes me cry, she lets me go
stative A state, not an action: not used with -ing I want (not I am wanting)

Takes Predicate — for linking verbs, what they can be followed by:

Value Example
adjective I feel sad, it tastes good
noun she became a doctor
place I am at home
existential there is food: only be

Semantic Category: activity marks a verb that can follow go: go walking, going shaving.

Takes Please: true lets a statement built on this verb end with please: I want a drink please. want, need and like have it. Without it, VoiceBox won’t offer I am tired please.

Passive: false — for an object-infinitive verb that has no passive: I want you to go is fine, I am wanted to go is not.

Auxiliaries (AUX)

The three helping verbs, be, do and have, which build tenses, questions and negatives: I am eating, Do you want tea?, I have eaten. be, do and have are also ordinary verbs. You are unlikely to need to add an auxiliary.

Modals (MODAL)

can, could, will, would, shall, should, may, might, must. A modal is followed by the plain verb (I can go, not I can goes) and starts a request (Can you help me?).

Adjectives (ADJ)

An adjective describes: a red jumper, I am tired. It can sit before a noun or after a linking verb.

Feature Use it for
Complement: infinitive Can be followed by to + verb: happy to help, ready to go.
Gradable: false Doesn’t come in degrees: dead, married. VoiceBox then doesn’t offer How dead is it?
Indefinite Article First sound differs from first letter: an honest answer.

An adjective of more than one syllable needs its comparative and superlative spelled out. See Comparing.

Adverbs (ADV)

An adverb adds when, where, how or how much. Where it can go is set by its features; an adverb with none of them is only reached through the A–Z list.

Feature Meaning Example
Position: pre Goes before the verb I always eat, I never go
Position: front Can start a sentence as a time Now I want to sleep
Position: end How much, after the verb or object it hurts a lot
Semantic Category: place A place I am here, go upstairs
Semantic Category: time + Tense A time I went home yesterday
Type: degree + Degree Scope Strengthens an adjective very tired (absolute), much better (comparative)
Particle: true Belongs to the verb, after its object turn the TV off, put it down
Polarity: negative Only after not or in a question Have you ever been?
Type: negation Only not

Pronouns (PRON)

Pronouns stand in for a noun. Each has an Agreement (see Agreement) and, for the personal pronouns, two forms:

Form key Use Example
nominative Subject, before the verb I am tired, she went
objective Object, after a verb or preposition help me, with her
Feature Use it for
Type: reflexive myself, yourself, themselves…: used when the object is the subject (I hurt myself).
Type: possessive mine, yours, ours…: stands alone (it is mine).
Same As Subject On I, we and you only: stops I hurt me, so the reflexive is used instead.

there, as in there is some food, is a pronoun in VoiceBox and a place adverb too (I am there).

Possessives (POSS)

my, your, his, her, its, our, their. A possessive comes before a noun, in place of the or a: my mum, your shoes. It works with singular and plural nouns. For the possessive that stands alone (mine, yours) use a pronoun with Type: possessive.

Determiners (DET)

A determiner comes first in a noun phrase and decides whether the noun is singular, plural or uncountable. The Definiteness feature says which kind it is:

Definiteness Words Noun that follows
definite the singular or plural
indefinite a, an, some, one, another, more, enough depends on Number
demonstrative this, that / these, those singular / plural
quantifier each, every / many, few, several, all, both / much singular / plural / uncountable
existential any plural or uncountable
negative no plural or uncountable

Other determiner features:

Feature Use it for
Number Whether the following noun is singular or plural.
Countability Set uncountable if it can come before an uncountable noun (some water).
Agreement Whether the phrase counts as singular (3sg) or plural (3pl) for the verb.
Stands Alone: true Can be used with no noun after it: I want some, I like this. Not a, every or no.
Determiner Role predeterminer goes before another determiner (all the cake, both my hands); postdeterminer goes after one (the next day, my first time).
Proximity near (this, these) or far (that, those).
Tense For last / next / this as times: last week is past.

Prepositions (ADP)

Words of place, time and relation: in, on, at, to, with, after. A preposition is followed by a noun phrase or pronoun: in the kitchen, with me.

Feature Use it for
Semantic Category: time Makes a time phrase: after lunch, until tomorrow. Such a phrase can also start a sentence: After lunch I want to sleep.
Comparison: true Only than, which follows a comparative (bigger than me).

Interjections (INTJ)

Words that stand on their own: yes, no, hello, sorry, ouch, thank you. Any interjection can be a whole sentence (Hello.). Some set phrases are built in: yes please, no thank you, and please at the start or end of a request or command.

Question words (WH)

what, where, when, why, how, who, which. A question word starts a question and stands for the part of the answer that is missing. Wh Slot says what that part can be:

Wh Slot It stands for… Example
be-complement what comes after is / are What is it?, Where is she?
object the object of the verb What do you want?, Who did you see?
adjunct a reason, time or place added to a complete sentence Why do you like her?, When did you go?
linking how someone feels or seems How do you feel?

This is what stops nonsense such as What do you like her? or Why do you want?.

Punctuation (PUNCT)

. ends a statement, ? ends a question, and 's makes a name possessive (Sam’s coat). Type: possessive marks the 's.

3. Basic sentence structure

Every sentence is one of a few kinds. VoiceBox ends each one for you with . or ?.

Statements

The basic English order is subject → verb → the rest:

Subject Verb part The rest
I want a drink object
She is tired description
My mum went to the shop place
I gave him the book two objects
It makes me sad object + description
I know you are tired another sentence

The subject can be a pronoun (I, she), a name (Sam), a noun phrase (the nurse, my feet, some people) or two of these joined by and (my mum and I).

The verb part can be several words, which is how English shows tense and mood: want, wanted, do not want, will want, am going to want, have wanted, can not stop.

The rest depends on the verb (see the verb features above). After it you can add, in this order:

  1. a place: …in the kitchen, …here
  2. a reason, with to: …to see my mum
  3. a time: …tomorrow, …after lunch

For example: I went to the hospital to see my mum yesterday.

A time can also come first: Yesterday I went home, On Wednesday I was sick. Only adverbs marked Position: front and time phrases can start a sentence like this.

A noun phrase inside any of these is built as:

determiner or possessive → up to two adjectives → noun

the big red ball, my new shoes, some hot tea. Two adjectives can also be joined with and: the black and white dog.

Questions

Kind Pattern Example
Yes/no with be be → subject → the rest Are you tired?, Is she coming?
Yes/no with do do → subject → plain verb → the rest Do you want tea?, Did she go home?
Yes/no with have have → subject → past participle Have you eaten?
Is there… be → there → noun Is there any water?
Wh-question question word → be/do/have/modal → subject → … What do you want?, Where are you going?
How + adjective how → adjective → be → subject How old are you?
How many / much how many/much (+ noun) → … How much water did you drink?
What / which + noun what/which → noun → … What time is it?, Which one do you want?

Requests

A modal → subject → plain verb: Can you help me?, Could I have a drink?, Will you stay?. please can go at the start or, if the modal allows it, at the end.

Commands

A plain verb with no subject: Help me, Sit down, Be careful, Don’t go. please can go at either end: Please help me, Help me please.

Joined sentences

Two statements can be joined by and, but, or or a linking word such as because, if or when: I went home because I was tired.

Short replies

An interjection alone (Yes., Hello., Sorry.) or the set phrases yes please and no thank you.

4. Plurals

Countable and uncountable

Only countable nouns have a plural. VoiceBox chooses singular or plural from the words around the noun:

Before the noun Noun is Example
a, an, one, another, each, every, this, that singular a cup, this shoe
these, those, many, few, several, both, all plural these shoes, many people
the, my, your, no, any, some either the cup / the cups
nothing plural (countable) or uncountable I want biscuits, I want water

One tile for both

Where both singular and plural would be correct, the grid shows one tile with the plural ending in brackets, such as eye (s). Tap it and choose eye or eyes. An irregular plural is written out: foot (feet). Where only one is correct, the tile goes straight in.

How plurals are spelled

VoiceBox makes regular plurals for you. These are the rules it uses:

Word ends in Rule Example
s, x, z, ch, sh add -es bus → buses, box → boxes, dish → dishes
consonant + y y → -ies baby → babies (but toy → toys)
f or fe → -ves knife → knives, leaf → leaves
consonant + o add -oes tomato → tomatoes
anything else add -s cup → cups

Add a plural form when the rules get it wrong. Common cases:

To add one, tap Add Form, type plural as the key and the plural spelling as the value.

5. Agreement

Agreement means that words which belong together match. VoiceBox enforces it, so you never have to choose between is and are.

Person and number codes

Agreement values are written as a person (1, 2, 3) and a number (singular, plural):

Code Meaning Words
1sg I I
2sg you (one person) you
3sg he, she, it, one thing he, she, it, my mum, the cup, water, Sam
1pl we we
2pl you (more than one) you
3pl they, several things they, my feet, the people, my mum and I

Subject and verb

The verb matches its subject.

What counts as the subject’s number:

Determiner and noun

The determiner and noun agree in number: this shoe, these shoes, not these shoe. See Plurals.

Pronoun case

A pronoun takes its subject form before the verb and its object form after it: I saw her, she saw me. That is why each personal pronoun has nominative and objective forms.

Reflexives

When the object is the same person as the subject, English uses the -self form: I hurt myself, not I hurt me. The reflexive agrees with the subject: she hurt herself, we hurt ourselves. he, she, it and they don’t need this check, because she hurt her can mean someone else.

Modals and their subjects

Each modal’s Agreement lists the subjects it can take: May I…? but not May you…?; Shall I…? and Shall we…? only.

a and an

There is a single a tile. VoiceBox writes a or an when it shows the sentence, according to the next word, adjectives included: a cup, an apple, an empty cup. It goes by the first letter, so a word whose first sound is different needs the Indefinite Article feature: an on hour and honest, a on university, one and European.

6. Verb forms and tense

The forms of a verb

Form key Use Regular rule Example
base after to, do, modals; commands the word itself eat
3sg present, after he/she/it add -s / -es / -ies eats
past simple past add -ed ate
participle after have, and the passive (was told) add -ed eaten
gerund the -ing form add -ing eating

The regular rules handle walk → walks, walked, walking, cry → cries, cried, and bake → baked, baking. Spell out a form when:

Tenses VoiceBox AAC can build

Tense Example
Present I eat, she eats, I do not eat
Present continuous I am eating
Past I ate, I did not eat
Past continuous I was eating
Present perfect I have eaten
Past perfect I had eaten
Future I will eat, I am going to eat, I am about to eat
With a modal I can eat, I should eat, I might eat
Passive I was told to rest, it was broken

Verbs marked stative (such as want, love, know) are left out of the -ing tenses: I want, not I am wanting.

The tense filter

The Past / Present / Future buttons show only sentences in that tense. All shows everything. A filter applies to the whole sentence, so I know you ate needs All.

Time words and tense

Time words have to fit the tense: I went home yesterday, not I will go home yesterday. Each time word lists the tenses it fits in its Tense feature:

Word Tense
yesterday, last week past
tomorrow, next week, soon present, future
again, later, today past, present, future

“Present” includes the future: I will eat tomorrow and I am visiting tomorrow are built as present. A new time word needs a Tense feature, or it won’t be offered.

A time at the start of a sentence fixes the tense of the rest: after Yesterday… VoiceBox offers only past verbs.

Time phrases are built from:

7. Other features of English

Negatives

not comes after the first helping verb: I am not tired, I can not go, I have not eaten. A plain verb needs do: I do not want it, she did not go. Commands use don’t: Don’t go. A word with Polarity: negative such as ever only appears after not or in a question: I have not ever…, Have you ever…?.

Comparing: happier, the happiest

Adjectives have a comparative and superlative form: happier than you, the happiest, much better. The regular rules are:

Adjective Rule Example
ends in e add -r, -st nice → nicer, nicest
ends in consonant + y -ier, -iest happy → happier, happiest
one syllable, consonant–vowel–consonant double the last letter big → bigger, biggest
anything else add -er, -est cold → colder, coldest

Spell out both forms for:

Degree adverbs pair with the right form: very with the plain form (very tired), much with the comparative (much better), a bit with either. That is the Degree Scope feature.

Places: at home, in bed

Most places need the or my: in the kitchen, to my room. A few English places go without, and Bare Locative lists which preposition allows it: home (at), bed and hospital (in, to), church and work (at, to).

Verbs with particles: turn it off

Some verbs come with a small word that belongs to them: turn off, put down, pick up. In VoiceBox the small word comes after the object (turn the TV off, put it down) and needs Particle: true. on, off, up, down, back, out and away have it.

please

please can end:

Questions that aren’t requests don’t take please.

Joining words with and / or

Only two things are joined, never a list.

to + verb

A verb with Verb Subcategory: infinitive, or an adjective with Complement: infinitive, is followed by to + verb: I want to go, I am happy to help. to + verb can also give a reason at the end of a sentence: I need food to feel better.

Possession

Three ways, all supported:

Placeholders: ??? and 123?

The ??? tile is for a word that isn’t in the dictionary. It can be a noun, name, verb or determiner, and you type the word when you tap it. 123? is for a number (I want 3 drinks).

8. Known limits

VoiceBox does not yet handle all of English. These are the gaps you are most likely to notice:

9. Quick reference: forms and features

Form keys

Type these exactly as the key in Add Form.

Key Part of speech Meaning
singular NOUN singular spelling
plural NOUN plural spelling
base VERB, AUX, ADJ plain form
3sg VERB, AUX he/she/it present
past VERB, AUX simple past
participle VERB, AUX after have; passive
gerund VERB, AUX -ing form
1sg 2sg 1pl 2pl 3pl AUX present for each person (be)
1sg-past … 3pl-past AUX past for each person (be)
nominative PRON subject form (I)
objective PRON object form (me)
comparative ADJ -er / more …
superlative ADJ -est / most …

Features by part of speech

Part of speech Features
NOUN Countability, Number, Bare Locative, Indefinite Article, Semantic Category, Tense, Time With
PROPN Countability, Agreement, Indefinite Article
VERB Transitivity, Verb Subcategory, Takes Predicate, Takes Please, Passive, Semantic Category, Motion Verb, Agreement
AUX Agreement
MODAL Agreement, Takes Please
ADJ Complement, Gradable, Indefinite Article
ADV Position, Semantic Category, Tense, Type, Degree Scope, Particle, Polarity
PRON Agreement, Type, Same As Subject
POSS Agreement
DET Definiteness, Number, Countability, Agreement, Stands Alone, Determiner Role, Proximity, Tense
ADP Semantic Category, Comparison
INTJ Takes Please
WH Wh Slot
PUNCT Type

Checklist for a new word