Pronunciation guide: IPA symbols, stress and word endings

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.

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)

-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.

underestimate

/ʌndɚˈɛs.tɪ.meɪt/ verb, noun

Forms underestimates underestimating underestimated

verb (transitive) To estimate too low; to perceive (someone or something) as having a lower value, quantity, worth, etc., than what he/she/it actually has.
verb (transitive) To perceive or expect (someone or something) to be less significant or difficult than it actually is. “I totally underestimated the task.”
noun An estimate that is too low.

Synonyms

From under- + estimate.

Sources: Wiktionary · WordNet 3.0 · Webster’s 1913 — from the Wiktionary entry “underestimate”, CC BY-SA 4.0. Details