Learners often say government as "govern-MENT," giving the ending a strong, clear vowel. Native speakers do the opposite: in nouns, the -ment ending collapses into a quiet schwa, /mənt/, sounding like "muhnt." So it is GUV-ern-muhnt, MO-muhnt, DOC-yuh-muhnt.
The twist: when a word can also be a verb, that same ending wakes up into a full /ment/. This one contrast sharpens dozens of common words.
The Rule
Nouns: -ment = /mənt/ (reduced). The suffix is unstressed, so its vowel shrinks to schwa: government, moment, document, argument, movement, agreement, development, department, apartment, environment, equipment. Never stress the ending.
Verbs: -ment = /ment/ (full). When the same spelling is a verb, the last syllable takes a light secondary stress and the vowel opens up. Compare the noun DOCument /ˈdɑːkjəmənt/ with the verb to DOCuMENT /ˈdɑːkjuˌment/; the noun COMpliment with the verb to compliMENT; and the same pattern in experiment, implement, supplement, complement, ornament, segment. The reduced ending signals "noun"; the full ending signals "verb."
Practice Words
Words That Always Keep the Full Vowel
A few -ment words are not the noun suffix at all; the ending carries the main stress and always uses full /ment/: cement /sɪˈment/, lament /ləˈment/, augment, ferment (verb), and torment as a verb. In these, the stress falls on the final syllable, so there is no schwa. If -ment is the stressed syllable, keep the vowel; if it is an unstressed noun ending, reduce it.
Quick Tip
Whisper the noun ending like the word aren't without the vowel: "mnt." That near-vowel-less mumble is exactly right for government and moment. Save the clear "ment" for when you are using the word as an action.