Q&A: If the head of government of the Republic of Ireland is widely known as the Taoiseach, why isn’t the head of government of Israel widely known by a Hebrew term rather than as “Prime Minister”?

Three reasons:

1. Because only the Irish Prime Minister is accorded this honour (the PM of France isn’t referred to in English as the Premier Ministre, the Spanish PM isn’t called the Primer Ministro, etc.)
2. Because Rosh Hamemshalah is a bit of a mouthful for most foreigners
   and—last but not least:
3. Because foreign Jews would confuse the Israeli PM with Rosh Hashanah, and think that he must be celebrated only once a year.