Tenuis nasal consonants

Question

We know that, for plosives, when the voice onset time is before the closure event, the consonant is voiced, like [b]; if about the same time, it is tenuis, like [p]; if after, it is aspirated, like [pʰ]. Clearly, the aspirated-tenuis distinction for plosives and affricates exists in many languages. Wikipedia says aspirated-tenuis distinction for fricatives also exists in some languages.

But how about nasals? We know that [mʰ] is possible, and there are languages, like Burmese, that has distinction on [m] and [mʰ]. But what is the tenuis [m]? Can it be that the tenuis is actually [j̃m] (nasal approximant preceding [m]) or [mp] (prenasalized plosive)? If not, what is it? Do some languages have aspirated-tenuis nasal distinction? Or if it does not exist, what is the biological restriction on it?

Answer 1

The term "tenuis" in linguistics is not an absolute phonetic description, it is a relative term, similar to "unmarked". The consonant b is voiced, the consonant p is not. When describing an instance of p as being tenuis (or not), that presupposed that you are talking about kinds of p, in which case you might be dealing with [pʰ], [p'] or [p]. "Tenuis" simply means "plain", not having other (laryngeal) things added to it. m is inherently voiced. Nasals can have added laryngeal features such as glottalization or aspiration, two broad phonological categories. "Glottalized nasals" may be phonetically realized with creaky voice throughout, or with glottal closure within the nasal, it just depends on the language. "Aspiration" of a nasal can likewise be realized as breathy voicing (as in Shona), or voicelessness with higher airflow (as in Tibetan, or Gogo). There can even be nasals where voicing simply isn't present, but there is no special higher-airflow associated with the nasal – this is the situation with Angas, which is reported to have prepausal devoicing of sonorants (I would say more accurately that voicing died prematurely in prepausal position).

So m is plain = tenuis, but you can make a non-plain m, then you call it something else.

Answer 2

Tenuis is a term used to refer to voiceless plosives [p, t, k], especially ones that are unaspirated, so it doesn't apply to [m], which is by definition voiced.

Burmese has voiceless [m̥], but not aspirated [mʰ]. Burmese /m̥/ is typically partially voiced [m̥͡m] according to Watkins (2001), so that realization can be considered as having a negative VOT.