Is the word "on" pronounced like /ʌn/ or /ən/ instead of /ɔn/ when it is unstressed? [duplicate]

Is the word "on" pronounced like /ʌn/ or /ən/ instead of /ɔn/ when it is unstressed in an American accent?

Solution 1:

Pronunciation of the preposition or particle on is affected by the cot-caught merger, fully complete in many areas of North America, though far less so in the American South. In dialects with the merger, on sounds like /ɒn/ and /ɔn/ in those without. English, Australian, and New Zealand accents generally remain unaffected while most Scottish accents have merged the other way.

In any variety of American English, the vowel in on never reduces to a schwa, in contrast, say, to with, which in rapid speech can reduce the vowel to schwa and elide the th if followed by the equally reduced definite article the. In this respect, on is like off and up, whose vowels never reduce, but unlike to, which does.

Solution 2:

No, on does not have a weak form. It is always pronounced with a full vowel as /ɒn/ (mainly British English), /ɑn/ (American English without low back merger), /ɔn/, etc.

Here are some sources sharing this view:

• "Note: There is no weak form for on /ɒn/." (from: Low, E. (2015) Pronunciation for English as an International Language. New York, Routledge.)
• "on ɒn ɑ:n ɔ:n" [note, the entry makes no mention of a weak form] (from: Wells, J. C. (2008) Longman Pronunciation Dictionary. Harlow: Longman.)
• "The preposition on has no weak form" (from: Burleigh, P & Skandera P. (2016) A Manual of English Phonetics and Phonology. Tübingen: Narr.)
• "Prepositions [...] a few have no weak forms: off, on, up." (from a handout produced by a lecturer at the Unversity of Brunei Darussalem)
• "< on > DOES NOT HAVE A WEAK FORM REDUCED TO SHWA!" (from a handout produced by a lecturer at the University of Lublin, Poland)
• "The following function words have no weak form, no matter how unstressed they are: did, may, might, in /ɪn/, on /ɒn/, with /wið/, off /ɒf/, up /ʌp/" (from a scanned page of a phonology text book, found here)