The word estimate can be read as either a noun or a verb.
The meanings are closely related, but the pronunciation of the two varies in the final syllable.
- The noun 'an estimate' has the sound of the schwa or the vowel 'i' in the last syllable, while the first syllable is quite strongly stressed: 'EST-i-mut', IPA: /'ɛs tɪ mə(or ɪ)t/'
- The verb 'to estimate' has a clearer '-a-' vowel in the last syllable, like the sound of the last syllable in 'calculate' and 'relate'. This makes the stress on the first syllable slightly less than in the noun - but it is still the principal stress in the word, IPA: /'ɛs tɪ ,meɪt/.