It is closely related to the Chaga languages of Kenya and Tanzania.
The Saghala (Northern Sagala, Sagalla) variety is distinct enough to be considered a language separate from the Daw'ida and Kasigau dialects.
[2] Daw'ida and Saghala contain loanwords from two different South Cushitic languages, called Taita Cushitic, which are now extinct.
[3] It is likely that the Cushitic speakers were assimilated fairly recently, since lateral obstruents in the loanwords were still pronounced as such within living memory.
However, it's a distinct language, lexically and grammatically closest to Chasu (Pare).