Apus Theory

Introduction

The rules used to 'chord' words are described here, however it is not productive to try to memorize these rules. The best way to improve your chording is to simply practice and absorb the chords through repetition.

A suitable exercise is as follows:

Find a short passage to practice, based on your normal material, of 100-300 words.
Start typing it, using chords where you can and the rest in completion mode,
Each time you get a 'tip' showing you a missed chord, backspace and chord it instead.
Repeat until you can enter the whole passage without any missed-chord tips.
Drill the passage until you can chord it at your target speed

Overview

Apus is almost entirely phonetic, the keys pressed are based on the sound of the words.

Each chord usually represents a single syllable. Syllables typically consists of initial consonants, then a vowel, then final consonants. The initial consonants are entered with the left hand and the final ones with the right hand.

The tables below give the mapping of keys to sounds using the IPA.

Key Mappings

Some sounds are entered with a single key, others with a combination.

There are a few duplicate key combinations, mostly these are chosen in such a way that is no ambiguity, for example initial d͡ʒ is chorded with WR, which would otherwise chord ðm, however ðm does not occur as an initial consonant cluster in English.

There are also a few duplicate key combinations where the sounds are similar, e.g. ʒ and ʃ. The two rarest initial consonants z and k also share a key. Duplicate key combinations are marked like this.

The phonemes are given in frequency order.

Key to Tables

this style	=	formed by a combination of keys that do not individually combine to make the sound. A special combination
this style	=	a duplicate key combination
this style	=	a combination that is awkward to type and is generally avoided with substitutions

Initial Consonants

Initial Single Consonants

Initial Consonants
ipa	ð	w	t	ɾ	h	b	s	k	m	f
key	W	Q	S	S	E	V	D	T	R	C
ipa	d	ɹ	l	p	n	ɡ	d͡ʒ	ʃ	v	t͡ʃ
key	X	A	Z	F	FS	VC	WR	WQ	TW	WD
ipa	θ	z	ʒ	j
key	EW	T	WQ	XZ

Example: The word 'may' is chorded with 'R' alone. 'boy' is 'V' alone

Initial Consonant Clusters

Sometimes syllables start with more than one consonant before a vowel, e.g.: prey, fly. This is known as a 'consonant cluster' and is chorded simply by pressing the keys for each consonant together.

The most common ones are given below

Initial Clusters
ipa	pɹ	st	fɹ	tɹ	sp	bɹ	dɹ	stɹ	sk	kw
key	FA	SD	AC	AS	FD	AV	XA	SAD	TD	TQ
ipa	l	sm	fl	sl	tw	ɡl	sw	skɹ	spɹ	skw
key	Z	RD	CZ	ZD	SQ	ZVC	QD	ADT	DAF	DQT
ipa	pw	spl	sn	hw	pj
key	QF	FZD	FSD	EQ	FXZ

Example: ADT+IJ chords 'screens'. CZ+J chords 'flown'.

Some of these combinations are awkward to type and are generally avoided with substitutions. These are styled like this.

Special Initial Consonant Clusters

Some clusters are not formed from simple combinations of keys that represent each consonant in the cluster, these special combinations are given below

Initial Clusters (special)
ipa	θɹ	sf	vl
key	WA	DTW	CZ

Example: aw chords throw, dtw chords sphere

Final Consonants

See key

Final Single Consonants

Final Consonants
ipa	n	z	t	ɹ	v	d	l	ŋ	m	s
key	J	I	L	;	P	O	N	U	M	K
ipa	k	ð	p	t͡ʃ	f	d͡ʒ	θ	ʃ	b	ɡ
key	/	.	JP	,	PK	/,	/M	M,	PU	LP
ipa	ɾ	ʒ	ɣ
key	l	M,	LP

Examples: "/" chords 'echo', ";" chords 'air'

Final Consonant Clusters

Some clusters can appear in either order, e.g. '-st' or '-ts', for these, the least common cluster uses a special form

Final Clusters
ipa	nd	nt	st	nz	ns	ld	kt	ks	lz	zd
key	JO	JL	KL	IJ	JK	ON	/L	/K	NI	IO
ipa	ɹd	ndz	mz	nts	ɹt	ɹz	vd	pt	ps	ŋz
key	;O	JIO	MI	JKO	;L	I;	PO	PJL	JKP	UI
ipa	nst	lt	ŋk	vz	md	ft	kst	nd͡ʒ	ɹm	ɹts
key	JKL	NL	/U	PI	MO	KLP	/KL	,/J	M;	;KO
ipa	ʃt	ɹs	dnt	lp	fs	lv	thr	rk	rp	ksts
key	M,L	;K	JL	NP	PKM	NP	.;	./	JP OR .J/	/KO

Example: JO chords 'and'

Special Final Consonant Clusters

Some clusters are not formed from simple combinations of keys that represent each consonant in the cluster, these special combinations are given below

Final Clusters (special)
ipa	ɹd͡ʒ	dz	sts	lf	kts	sk
key	,;	LI	PIO	PNK	/KO	/I
ipa	fts	sks	ts	dnt	mp	ɹθ
key	POK	./K	OK	JL	MP	;.
ipa	pθs	d͡ʒd	lpt	lm	fz	ɹkt
key	JPK	,O	NL	/M	IP	/L
ipa	ɹp	ɹb	ɹv	ksθ	dst	nb
key	JP	JP	P	./K	IO	PU

Example: /i chords 'ask'

Vowels and Diphthongs

Most vowels (as used) do not have a non-space key, in this case simply the consonants are entered.

All diphthongs (in AmE) have a non-space key, and so do all 'long' vowels.

The space bar is pressed for all vowels apart from the 'front' (or 'smile') vowels, so short central or back vowels are represented with the space bar alone.

Vowels
ipa	a͡ɪ	o͡ʊ	uː	ɜː	ɑː	iː	ɔː	e͡ɪ	a͡ʊ	oː
key	Y	Y*	H*	B	G	H	B*	G*	GH	GH* or H*
ipa	i͡ə	ɔ͡ɪ	ɒ	a	ɐ	ʌ	ʊ	ɔ
key	BH	BH*	*	*	*	*	*	*

Key: * means the space bar.

The following dipthongs do not have a key, because they do not appear in AmE: ʊ͡ə, e͡ə, ə͡ʊ

These key combinations have special meanings (see substitutions and Start and End vowels): BY, GY. GY*

BY* is reserved for future use.

Start and End vowels

If a syllable has no initial consonant, then it is chorded with the vowel (if entered) and final consonants only. Similarly if it has no final consonant only initial consonants and vowels are keyed.

Some syllables consist of only a vowel sound - this is common at the start and end of words - and if the vowel has a non-space key, then that is used on its own. For syllables that consist of only a vowel that does not otherwise have a non-space key, the special combination GY (front vowels) or GY* (other vowels) is used.

Examples:

Special Vowels
chord	word
G+Y	our
R+J#G+*Y	mini

This syllable is often omitted (see contractions)

Substitutions

In some cases key combinations resulting from the above rules are difficult or impossible to chord, or can not be detected by keyboards, in this case some key combinations are substituted with others to make the words easier to chord.

The sound chorded by the substitution is always similar to the sound intended.

Some examples:

Words ending 'ɡd', 'ɹbd' or 'd͡ʒz' (e.g. intrigued, absorbed, cabbages) have the sound 'ə' inserted before the final consonant
The ʔn sound is replaced with 'tɛn' (examples: written, patent)
θ can be replaced with ð in clusters, e.g. 'ŋθ' is chorded with 'U.' and 'nθ' with 'J.'

Conflicts

In some cases following the above rules would result in different words having the same chordings. This is always the case with homophones (e.g. 'two' and 'too'). This is called a 'conflict'.

To avoid this some words are chorded slightly differently than they would be otherwise. In Apus each word with a chord has its own unique chord sequence.

The most common word has the regular chording and the least common one or ones is modified.

The rules that are applied in order are:

The end or start vowel is not entered where it is shown with G+Y or G+*Y.
If the word pronunciation starts with 'h' or 'w' and the spelling starts 'WH-', then it is chorded as if it was pronounced starting 'hw' (EQ)
The space key can be added or removed from the word
';' can be replaced with ' (this is the only time the apostrophe appears in chords, and is only used if it makes an easy to enter chord)
Some otherwise unused key combinations are used, e.g. ",./" in place of "/" , or "SV" for "V", etc
BY is used as a special chord for the word 'eye'

Examples:

Resolved Conflicts
chord	word
FS+YI	nose
FS+*YI	knows
E+*HI	whose
EQ+*HI	who's
*J#G	Anna
J#;	inner
*'	you're
*;	your

Contractions

To speed chording, some keys or whole syllables can be omitted where this does not create conflicts.

These rules are applied in order, each rule is only applied if it both makes for a faster chord sequence and does not create a conflict with another word.

If the chord sequence ends with a vowel, it is omitted
Other syllables consisting of only vowels are omitted.
If the sequence ends with a vowel, and the spelling ends with '-r', the the final vowel can be replaced with ';' (ɹ sound).
Other vowel keys (including the space bar) can be omitted.
Final chords can be omitted from the sequence (again, only if this does not create a conflict)

Example: d+. chords 'southern'

IPA

For a full list see wiktionary

Dipthongs
IPA	example
a͡ɪ	I, eye
e͡ɪ	pay
a͡ʊ	out, how (BrE)
o͡ʊ	those (AmE), also (AmE), (not in BrE)
ɔ͡ɪ	choice, join
i͡ə	severe (BrE), we're (BrE), idea (AmE)
ʊ͡ə	tourists, (not in AmE)
e͡ə	air (BrE), there (BrE), (not in AmE)
ə͡ʊ	those (BrE), also (BrE), (not in AmE)

Glossary

word	meaning
chord	A set of keys pressed in one movement
chording	A sequence of chords representing a word; the act of entering text using chords
phoneme	An indivisible phonetic unit, e.g. a consonant or vowel sound
consonant cluster	A set of consonants at the beginning or end of a syllable without a vowel
key combination	A set of keys pressed together to represent a phoneme
conflict	Different words with the same chording