Dear SIGARAB
Greetings
There are common words and linguistic similarities between languages spoken in Ethiopia and the Arabic varieties used in the Middle East and North Africa primarily due to shared "Semitic" linguistic roots, geographical proximity, and historical interactions. Amharic and Tigrinya are the major languages in the Ethiopian and Eritrean highlands, they share many cognates (words with a common origin) and similar grammatical structures.
We at Kalmasoft have spent the last five years extracting all the shared cognates in the many "Semitic" languages, publicly available while work still in progress through the following link.
Tigrinya, in particular, has a significant amount of the shared vocabulary due to it being the closest language to Arabic in terms of phonological and semantic features while Amharic, on the other hand, proved to have much in common in all syntactic aspects.
Both have a clear and evident contribution to the classic and modern Arabic including different subtle grammatical tools and classes largely attributed to Arabic due to insufficient researches that takes into account the existence of such relationships.
Regards
Hatim Ibrahim