Sound change and alternation
Lenition (weakening)
Sonorization (voicing)
Spirantization (assibilation)
Rhotacism (change of [z] or [d] to [r])
L-vocalization (change of [l] to [w])
Debuccalization (loss of place)
Epenthesis (addition)
Coarticulation
Palatalization (before front vowels)
Velarization (before back vowels)
Labialization (before rounded vowels)
Initial voicing (before a vowel)
Final devoicing (before silence)
Nasalization
Metaphony (vowel harmony, umlaut)
Consonant harmony

Sound change τ τ