^[g] and [ɢ] are contrastive in Ulaanbaatar Mongolian, but are allophones of the single phoneme /g/ in some other dialects.
^Always follows another consonant, and usually modifies the sound with iotation (unless used before е, in which case it is unpronounced).
^ abь is occasionally used before е to indicate that its pronunciation should not be blended with the consonant before it (as its sound is iotated); likewise, ъ serves the same purpose before я and ё.