Typology

Nyakyusa is registered as M.31 in the list of Bantu languages. It is the only
language in group M.30. Group M is put together more on a geographical than on
a linguistic basis and one should not expect too many similarities within the
group. Nyakyusa is one of the relatively few Bantu languages that doesn't make
use of tones, but it also differs substantially from surrounding languages in
terms of vocabulary. A monolingual speaker of Nyakyusa can not understand any
other Bantu language. 

The "tree-structure" for Nyakyusa in the Niger-Cordofanian family:

Niger-Cordofanian
    Niger-Congo
        Benue-Congo
            Bantoid
                M31
                    Nyakyusa

The languages in group M are (Guthrie 1967):

  M 10      M 20      M 30      M 40      M 50      M 60
1 Pimbwe    Wanda     Nyakyusa  Taabwa    Biisa     Lenje
2 Rungwa    Mwanga              Bemba     Lala      Soli
3 Fipa      Nyiha               Swaka     Ila
4 Rungu     Malila              Lamba     Tonga
5 Mambwe    Safwa               Seba	
6           Iwa				
7           Tembo				

Based on newer research with comparative wordlists it seems that the languages
which come closest to Nyakyusa are the languages along the Zambian border. 

(excerpt from the Nyakyusa dictionary)