Pronunciation guide: IPA symbols, stress and word endings

Vowels

iː	see	ɪ	sit	e / ɛ	bed	æ	cat
ɑː	father	ɒ	hot (UK)	ɔː	law	ʊ	put
uː	too	ʌ	cup	ɜː	bird	ə	about
eɪ	day	aɪ	my	ɔɪ	boy	aʊ	now
əʊ / oʊ	go (UK / US)	ɪə	near	eə	hair	ʊə	tour

Consonants that look unusual

θ	thin	ð	this	ʃ	she	ʒ	measure
tʃ	church	dʒ	judge	ŋ	sing	j	yes

p b t d k g f v s z h m n l r w sound as in ordinary English spelling.

Marks

ˈ main stress, before the stressed syllable: /ˈwɔːtə/ water · ˌ lighter (secondary) stress: /ˌʌndəˈstænd/ understand
ː a long vowel · (r) an r said only in accents that pronounce it (most American, Scottish, Irish)

Common word endings

-s / -es (plurals; he/she form of verbs): /s/ after voiceless sounds (cats), /z/ after voiced (dogs), /ɪz/ after s, z, sh, ch, j sounds (buses, watches). Spelling: -es after s, x, z, ch, sh; consonant + y → -ies (city → cities).
-ed (past): /t/ after voiceless sounds (walked), /d/ after voiced (played), /ɪd/ after t or d (wanted). Spelling: love → loved, stop → stopped, carry → carried.
-ing: make → making, run → running, see → seeing.
Irregular: go, went, gone · be, was, been · see, saw, seen · man → men · child → children · mouse → mice.
Older (King James) forms: -eth = -s (he loveth = he loves) · -est with “thou” (thou lovest) · spake = spoke.

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acid test

/ˌæsɪd ˈtɛst/ noun

Forms acid tests

noun (chemistry) A test involving the reaction of an acid with another chemical.
noun (figuratively) A rigorous test or appraisal of the quality or worth of something.
noun (by extension, historical) In the 1960s, a party based around the use and advocacy of the psychedelic drug LSD (known in slang as acid).

Etymology

From acid + test; sense 1 (“test involving the reaction of an acid with another chemical”) and sense 2 (“rigorous test or appraisal of the quality or worth of something”) refer to the use of nitric acid to test if a metal is gold; true gold is not affected by the acid.
Sense 3 (“party based around the use and advocacy of the psychedelic drug LSD”) is a pun referencing the slang term acid (“LSD”). The original “acid test” parties were thrown by the Merry Pranksters group between 1965 and 1966 and advertised by the slogan “Can you pass the acid test?”

Sources: Wiktionary — from the Wiktionary entry “acid test”, CC BY-SA 4.0. Details