While the other big West Germanic languages (e.g. German, Dutch) do often have progressive forms (Modern High German doesn't really, but spoken German does), they are usually less common and the simple present forms can also carry a progressive aspect.
It is hypothesised that Celtic influence did indeed play a role in the formation of the present progressive form in Modern English:
"One postulated source of the English current progressive aspect is the Celtic languages that have been spoken in Britain throughout its history, which all use a (to be)+preposition+verbal noun construction to form it."
"Rise of the periphrastic aspect, particularly the progressive form (i.e. BE verb-ing: I am writing, she was singing etc.). The progressive form developed in the change from Old English to Middle English. Similar constructs are rare in Germanic languages and not completely analogous. Celtic usage has chronological precedence and high usage. Celtic Englishes employ the structure more than Standard English. E.g. "It was meaning right the opposite", Manx English"
However, the progressive forms of Dutch, German, and the Celtic languages (and many other languages) all use constructions with prepositions (e. g. "at the eat-noun") instead of the English present participle construction, which is rather unique in this sense. See also this discussion:
Romanic languages use to be + gerund, without any prepositions, to form progressive tenses, e.g. Spanish - estoy leyendo- I am reading. English does the same. In modern English gerund=present participle in form, and it is still disputable which of them is used to form progressive tenses.
If this is not equivalent to "the boys are eating," then there should be some method of making it clear to the student that Irish has a separate continuous mood (formed, I would be willing to bet, with "tá"). From time to time, I get the idea that there is some instructional feature of this site that I am simply missing out on.
You can open this grammar site in your browser: http://www.nualeargais.ie/gnag/gram.htm For this question click on "the Verb" then click on "Tense and Mood" and you can click on "present tense" which is the progressive form that we have not learned yet and "habitual present tense" which, being easier, is the one we learned so far.