Why do japanese atonic verbs, who are supposed to have heiban accent pattern, end up to get an accent (and then a pitch fall) on the last mora when followed by such particles as か or の? I did not imagine, that until I read that Samuel Martin treated them as odaka (oxytonic) and I tested a few examples on the Suzuki-kun tutor of ojad. Much to my surprise, it turned out to be true that "suru" is atonic while "suru ka" has an accent on "ru", "shita"is atonic but "shita ka" has an accent on "ta". All books, websites and even ojad list of verbs consider atonic verbs to be heiban and not Odaka .
1 Answer
I don't think there's a clear "why" this happens it may just be how things developed though I would love to be wrong here.
If you're more interested in how it works you can refer to In what cases do 平板 verbs change their pitch? for more info.
Essentially certain particles can attach low onto 平板 verbs and longer particles and double particles in general also have their own general tendencies for how they operate both in 平板 and 起伏 verbs respectively.
As for 尾高 verbs from a labeling perspective it's a bit odd since really the PA of verbs operates on a binary level between 平板 (flat) and 起伏 (contains a downstep) so trying to replace 平板 verbs calling them 尾高 verbs is a bit strange since 尾高 is considered part of 起伏. The existence of certain particles attaching low onto 平板 verbs isn't really grounds to shift the fundamental verb classification from 平板 to 尾高 especially since most of the conjugations stay 平板, many particles still attach high and distinction between 平板 and 起伏 is a clear binary to draw.
There's a similar line of thought for 頭高 verbs. In reality all the 起伏 verbs share the same basic conjugations so trying to create more labels isn't really necessary.
