غاق: imitation of the crow’s call — type 1.
نخ: a call used to make a camel kneel — type 2.
صَوْتُ الْغُرَابِ: an ordinary possessive construction; not itself an imitated cry.
أَنَاخَ: a past verb reporting an action, not a call.
Meaning alone does not determine a word’s grammatical function.