Received Pronunciation and ambiguity (users vs uses)

The noun user is pronounced /ju:zə/ in RP. Notice that unless it is followed by a vowel, there is no /r/ in this word.

The verb use is pronounced /ju:z/.

However, the noun use is pronounced /ju:s/. Notice that unlike the noun user the noun use has an /s/ and not a /z/.

The words users, uses (verb) and uses (noun) are all very similar in English. But none of the three are homophones with either of the other two.

The noun user has a schwa at the end and so the plural, users, ends with /əz/. Like the other two words it has no /r/, but is different from them in that it has a schwa.

The verb uses has a regular third person ending. Because the base of the verb ends in a sibilant—in this case /z/—we use an /ɪz/ suffix here. So this word is /ju:zɪz/. This is distinguished from the noun user by having a KIT vowel instead of a schwa before the final /z/.

The noun uses has a plural suffix, which follows exactly the same rule as the third person singular suffix described above. The base word ends in a sibilant, and therefore the suffix /ɪz/ is applied. However, the sibilant which triggers the use of the /ɪz/ in this case is not /z/ but /s/. So this word is distinguished from the noun uses by virtue of having a KIT vowel instead of a schwa. However, it is also easily distinguishable from both of the other two words by having an /s/ at the end of the first syllable instead of a /z/.

The transcriptions for these words are:

• /ju:zəz/ (users)
• /ju:zɪz/ (uses - verb)
• /ju:sɪz/ (uses - noun)

Notice that the first two words here are distinguishable in RP because RP has not seen a merger of the KIT and schwa vowels, unlike several other world Englishes.

They are not pronounced the same, even in non-rhotic dialects like RP.

The noun use is pronounced with /s/, the verb use is pronounced with /z/:

noun: /jus/, verb: /juz/

When these words are inflected with the -s affix many dictionaries represent the affix vowel with the 'schwa', /-əz/. However, the vowel actually used is somewhat higher; it may be represented with /ɪ/ or /ᵻ/. (See my answer to this question.)

plural noun: /jusᵻz/, 3sg verb: /juzᵻz/

The noun user, derived from the verb, employs the verb's /z/; and the -er affix does employ a mid-central vowel, the schwa. In non-rhotic dialects, where the /R/ phoneme is deleted, this yields:

/juzəz/.

just for lagniappe: Very careful speakers, like classically-trained actors and singers, may pronounce the unstressed -s affix with an unreduced vowel, /ɛz/; and they may lower the schwa in the unstressed -er affix to something in the neighbourhood of /ɑ/. But nobody cares, or even notices, except other classically-trained actors and singers.

No, uses and users are pronounced differently in RP.

uses /juzɪz/

users /juzəz/