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.

“interacts” is a form of

interact

UK /ɪn.təˈɹækt/ · US /ˌɪn.tɚˈækt/ verb, noun

Forms interacts interacting interacted

verb (of people) To engage in communication and other shared activities (with someone). “The way staff interact with each other during breaks can play an important role in the workplace.”
verb (of two or more things) To affect each other. “This medication can interact with alcohol, so it's best to avoid drinking while you're taking it.”
noun (dated) A short act or piece between others, as in a play; a break between acts.
noun (obsolete) Intermediate employment or time.
noun (social sciences) A pair or series of acts involving more than one person.

Synonyms

Pref. inter- + act. Cf. Entr'acte.

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