Complex sentence: Relationships with other languages have therefore been difficult to determine with certainty; however, it is almost certainly Afro-Asiatic, and many linguists consider Guanche to likely be one of, or to be related to, the Berber languages.
Split into simpler sentences: Relationships with other languages have therefore been difficult to determine with certainty. Many linguists propose that Guanche to likely be one of, or to be related to, the Berber languages.