Minimal Pair List Vowels 5 and 12, /ɑ/ versus /ə/ 11 pairs
The /ɑ/ vowel is usually spelled <ar> but we also find <a> in ta . The schwa, of course, can be spelled in a great many ways, not all of which are uniform in widespread usage. Thus the unstressed indefinite article an can be shown as 'n or un or 'un , while the hesitation sound /həm/ is represented in this dictionary as h'm but might just as well be hem or hum .
Since the schwa is always unstressed, while /ɑ/ is usually prominent, there are very few minimal pairs. Only two are proper minimal contrasts of dictionary words, namely forearm/forum and radar/raider . In the case of the hesitation word h'm , it is likely that the inflected forms would be pronounced with /hʌm/ rather than /həm/. In the other cases we have a contrast between a word and a weak form, i.e. the form of a function word that would occur in rapid speech. Isolating such weak forms for a contrastive exercise is a completely artificial endeavour.
With such a short list it makes no sense to calculate a density value or semantic loading.
ah a arm 'em cars cos forearm forum forearms forums harm h'm harmed h'mmed harming h'mming harms h'ms radar raider ta to