Comparison of ASCII phonetic alphabets

Most, tho not all of these are based on the IPA.

A brief introduction of the systems:

• X-SAMPA, a general extension of SAMPA designed to accommodate the entire IPA. Z-SAMPA, develop'd on the ZBB, is a fully backwards compatible extension that includes the Extensions to the IPA and various other symbols, such as true mid vowels. Z-SAMPA extensions are mark'd by a green background.
• CXS is another variation of X-SAMPA used mostly on the CONLANG list. It is not entirely backwards compatible.
• Kirshenbaum is a somewhat more limited system that makes good use of diacritics, but has to quickly resort to diacritics such as <trl> (yes, that's a pentagraph) to describe sounds outside its "core focus" of English phonetics.
• TIPA, used in LaTeX typesetting of IPA.
• Carrasquer (description needed)
• Branner (description needed)

I am purposely exclusing the Coutts-Barrett system, based on graphical mnemonics to suggest IPA letters. It is very non-compatible with all the other systems, both in the details (for example, '-d' for ð, or 'n)' for ŋ),a nd in being prefixing rather than postfixing. I've also never seen it in use anywhere!

Symbols expressible by means of diacritics are not included in the table.

Latin minuscules

Aluckily, just about everyone agrees that these should be equated with their IPA values. Tabulating these would be a waste of spacetime :-) Let's just remark on the habit of sometimes falling back on transcription based on some specific language's orthography. Common cases include <y> for /j/, which may be follo'd with <j> for /ʤ/ and <c> for /ʧ/ or /ʦ/. A good indicator of this type of transcription is seeing <š ž> for /ʃ ʒ/.

Standardized

There is little disagreement over these assignments. Exceptions in bold.

IPA	SAMPoids	Kirsh.	TIPA	Carr.	Brann.	Comments
ɑ	A	A	A	A	A
β	B	B	B	B	V	'V' is not illogical. Branner's smallcaps → caps standard also means 'B' will have to be /ʙ/.
ç	C	C	C	C	c"
ð	D	D	D	D	D
ɛ	E	E	E	E	E
ɪ	I	I	I	I	I
ɱ	F	M	M	M	M	SAMPA 'M' is /ɯ/.
ŋ	N	N	N	N	ng)	Branner 'N' is /ɴ/.
ɔ	O	O	O	O	O
ʃ	S	S	S	S	S
θ	T	T	T	T	T
ʊ	U	U	U	U	U
χ	X	X	X	X	X
ʏ	Y	I.	Y	Y	Y	Kirshenbaum breiks here the well-estabilish'd pattern to use capitals for lax vowels, instead going for the rounding diacritic. This is because 'Y' is /ø/. How this is supposed to be logical (as opposed to making 'e.' /ø/) escapes me.
ʒ	Z	Z	Z	Z	Z
ə	@	@	@	@	@
ʔ	?	?	P	?	?	TIPA may be, I think, unable to use the symbol '?'.
ː	:	:	:	:	:

Competing standards

Assignments that are fairly intuitiv, yet not sufficiently so.

An obvious subsection is the issue of IPA smallcaps. Branner and Kirshenbaum in some cases go for the graphically obvious substitution by the corresponding actual capitals. Other systems notice this too, but add some escape caracter, to be able to free the simple capitals to some other use.

IPA	SAMPoids	Kirsh.	TIPA	Carr.	Brann.	Comments
ɣ	G	Q	G	G	g"	Arguably /ɣ/ fits better together here, due to the pattern set by 'B D'.
ʎ	L	l^	L	L	y&	Kirshenbaum demonstrating its "palatal" diacritic, and Branner its graphical-mnemonic structure. Yet other assignments for 'L' exist, for example /ɬ/ in Uralistics.
ʁ	R	g" (??)	R	R*	R&
ʙ	B\	b<trl>	\;B	B"	B	Kirshenbaum goes with the 'B' = /β/ crowd, and switches to featural description.
ɢ	G\	G	\;G	G"	G
ʜ	H\			H"	H
ʟ	L\	L	\;L	L"	L
ɴ	N\	n"	\;N		N	Kirshenbaum has an "uvular" diacritic too.
ʀ	R\	r"		R"	R

IPA	X-SAMPA	CXS	Kirsh.	TIPA	Carr.	Brann.	Comments
æ	{	&	&		&	ae)	SAMPA is supposed to be on the premise that this "looks like A in smiley-view". Most others rather play into the graphical similarity combined with the mnemonic "and" ([ænd]!)
ɸ	p\	P	F	F	P	F	One of SAMPA's sillier features, IMHO. Considering the symmetry of 'T D', your author quite prefers 'P B'.

Numbers and punctuation

.	.	(??)		(??)	.	Syllable break
ˈ	"	'		'	'	Primary stress
ˌ	%	,		,	,	Secondary stress. Why the heck is SAMPA making this more difficult than needs be?

IPA	SAMPoids	Kirsh.	TIPA	Carr.	Brann.	Comments
ʼ	_>	`		`	`	Ejective apostrophe
◌̪	_d	[			[	Dental bridge
(N/A)	_<	`		"	$	Implosive. If ejectivs get to have a single diacritic, why not these too? Kirshenbaum cuts a corner by using the same symbol for both, making it difficult to transcribe voiceless implosivs tho. Carrasquer uses its all-purpose diacritic #1, the quotation mark. An exception worth noting is that /ʛ/ is however 'G*'. Similarly, Branner has 'j$' for /ʄ/.
(N/A)	`	.		.	r)	Retroflex