Beja is Afro-Asiatic* - either part of Cushitic or a separate branch, depending on who you ask - and happens to be among the most obviously similar languages to Semitic and to Berber. The noun morphology is already fairly suggestive:
|Beja definite article||Arabic noun endings||Kabyle obligatory prefix|
|Masculine nominative singular||u:-||-u||w-|
|Masculine accusative singular||o-||-a||a-|
|Feminine nominative singular||tu:-||-atu||t-|
|Feminine accusative singular||to-||-ata||ta-|
And the pronominal object suffixes add credence:
(Beja, apparently, has no third person suffixes.) However, what really clinches it is the verbal system. Beja has two principal classes of verbs: one that often takes prefixes, and one that usually just takes suffixes. In Semitic, the prefixes are used for the imperfect, and the suffixes developed from a stative (still to be seen in Akkadian) into a perfect; Berber mostly retains the prefixes, whereas only minor traces of the suffixes remain. The prefixes are especially telling:
|you (m.)||ti- -a||ta-||t- -ḍ|
|you (f.)||ti- -i||ta- -i:||t- -ḍ|
|you (pl.)||ti- -na||ta- -u:na||t- -m|
|they||i- -na||ya- -u:na||-n|
while the suffixes are best exemplified in Beja in the conditional mood:
|Beja||Arabic||Dahalo general non-past (Cushitic)|
Just for good measure, in the prefix verbs you also have a feature found in Akkadian (among other Semitic languages) and Berber but lost in Arabic: a present tense formed by doubling the middle radical (in Berber and Akkadian) or adding n before the middle radical (in Beja). Compare:
- Beja aktim ("I arrived") > akanti:m ("I arrive")
- Akkadian almad ("I learned") > alammad ("I am learning")*
- Tamasheq əlmədǎγ ("I learn", irrealis) > lammǎdǎγ ("I am learning", realis)
It's really remarkable, considering all this, that Afro-Asiatic research isn't more advanced. There are two etymological dictionaries out there, admittedly - Ehret's and Orel and Stolbova's - but, though valuable, they frequently disagree with each other, and neither has attained general acceptance.
* Some people think Afro-Asiatic is not proved. I can't think why. Omotic's membership is not entirely clear, but all the rest is just plain obvious.
* Previously misquoted forms corrected, thanks to Matthew Loran.