Speakers of Kymna must have regarded lip articulation as too arduous. Therefore, parallel to the rounded/unrounded classification of vowels, labial consonants were changed in several stages of delabialization.
Proto-Tallic *p was a very productive consonant, in particular initially, and suffered most changes in Kymna. Similar to the development in Celtic, it was lost medially, before and after sonorants (*ps > *ks > ss), although it was retained initially before vowels (aspirated in the modern language).
√pran: K. ranna ’lying across’, ranga ’bridge’ (T. pran, prangá)
√pru: K. poru ’up, above’, pyru ’down, below’ (T. parú, pirú)
√tapl: K. toulum ’to speak, say’ (T. táplun)
√prubs: K. orudza ’tower’ < *a-prusba (T. parúzba)
Proto-Tallic *t spirantizes before and after sonorants to þ, disappears before l, and remains unchanged otherwise (aspirated in the modern language). Moluma eliminates interdental spirants in a fashion similar to Latin: *þ > f, *nþ > nd.
√thatn: K. soþynum ’elapse, to take (of time)’, dissim. of *þoþnum, M. sofnum
√tazl: K. tadzal ’blood’ (T. tálza)
√tlep: K. lëyum, lëym ’to shine’ (T. tlépun ’blink’)
Proto-Tallic *k spirantizes before sonorants to ch, after sonorants to h, disappears initially before s (medially *[ks] > *[xs] > ss, occasionally > ch); and remains unchanged otherwise (aspirated in the modern language).
Proto-Tallic *b early underwent betacism to v (first bilabial, eventually labio-dental) in all positions. A later weakening led to vr-, vl- > wr-, wl-.
√bradn: K. wrounum ’to fight’ (T. bráznun)
√bwo: K. vō ’mouth’ (T. bno)
√pobl: K. povle ’language’ (T. póble ’speech’)
Hence the phoneme b does not exist in classical Kymna. There is however an irregular exception: K. eble ’lip’ < *ai-peple (originally dual). It might be a dialectal loan from Moluma (where it takes the form aeble) which does have b, but can be in any case attributed to the suggestive quality of a labial sound in the word for ’lip’.
Proto-Tallic *d becomes ð medially, disappears before l, but remains initially and in the combination nd. The cluster dn changed dn > *ðn > n with compensatory lengthening. Moluma elminates interdental spirants after the fashion of Latin: ð> b in proximity to r, otherwise > d.
√khodr: K. soðrum ’to kill, destroy’, M. sobrum (T. hódrun ’to destroy’)
√bradn: K. wrounum ’to fight’ < *vroðnum (T. bráznun)
√daq: K. dālin ’stone’ (T. dat ’stone’, daklin ’pebble’)
√dlon: K. ilonna ’asleep’ < *i-dlon-na (T. dilón ’state of being asleep’)
Proto-Tallic *g was retained initially, but became a velar spirant *γ medially, except for ng. It fell away with compensatory lengthening before consonants, but was retained as h after sonorants and often between vowels, although in colloquial speech it usually drops between vowels as well.
√pogn: K. pounum ’to decide’ (T. pógnun)
√gam: K. gom(i) ’nose’ (T. gáme)
√khag: K. sohum, soum ’to eat’ (T. aχágun ’to eat, consume, absorb’)
Proto-Tallic aspirated *ph early became the spirant *f (by the same time *b, *d, *g became spirants), but during the delabialization process it changed to -ch- medially, h- initially and was only retained before and after u (sometimes o) and in initial fl-, fr-.
√phoks: K. hoss ’hair’ (T. ϕóska ’a single hair’)
√gaphn: K. gacha ’fish’ (T. gámϕa)
√phu: K. fū ’air’ (T. ϕu, ϕúχa)
Proto-Tallic aspirated *th > þ, but sometimes > fr-, fl- instead or beside þr-, þl- (similar to Gothic). Moluma eliminates the interdental spirants: *þ > f, *nþ > nd.
√tethr: K. tëfrum ’to find’ (T. atéθrun ’to find unexpectedly’)
√this: K. þydzum ’to show’, M. fydzum (T. θíssun ’to show’)
Aspiration was a modificational technique in Proto-Tallic, but it seems that it was coupled with palatalization in Kymna in the case of *k. Hence only palatal [kjh] appeared, spirantized to [ç] rather than [x] and later usually progressed to s, but to h before i, y and after l, r (cf. the ruki sound shift). In Moluma, [ç] became sh which is [ɕ] before front vowels and [ʃ] otherwise. Initially, *[kjhl-, kjhɾ-] > l-, r-.
√khomn: K. sumun ’sound’, M. shumun (T. hómne)
√khlob: K. lovum ’to get wet’ (T. hlóbun ’to drink’)
√khatj: K. sasa ’egg’, seita ’bud’, M. shasa, shaeta (T. háti, háita)
√khwetn: K. hynta ’leaf’ (T. hwénta)
√kwor: K. korhorum ’to grow (ipf.)’ < *kworkhworun, M. korshorum (T. kwor ’plant’)