Before I started learning Gaelic, the only languages I had learnt to any reasonable degree were Romance languages (French and Spanish) and Germanic languages (German and my native language, English). All of these languages follow a fairly “standard” (for European languages) Subject-Verb-Object (or SVO) pattern.
Of course, there are exceptions. Depending on the context, a German verb can come either before the subject or at the end of the sentence, as well as in the standard second position. In Spanish, the subject pronoun is almost always omitted because the verb conjugates in such a way as to make it largely unnecessary.
Gaelic, however, is nothing like that. I guess you couldn’t even really say that it’s a VSO structure, because in almost all cases, the “verb” is actually two – an “auxiliary” such as tha, chan eil, bha, and so forth, and a “continuous participle” such as ag ràdh or ag ionnsachadh or a’ coiseachd.
Verbs don’t really conjugate in the traditional sense, either. Compare this (and keep in mind that these are all irregular verbs!):
English: to be; I am, you are, he/she/one/it is, we are, you are, they are.
Français: être (to be); je suis (I am), tu es (you are), il/elle/on est (he/she/one is), nous sommes (we are), vous êtes (you are), ils/elles sont (they are).
Español: estar (to be); estoy (I am), estás (you are), está (he/she/you are), estamos (we are), estáis (you are), están (they/you are).
Deutsch: sein (to be); ich bin (I am), du bist (you are), er/sie/es ist (he/she/it is), wir sind (we are), ihr seid (you are), sie/Sie sind (they/you are).
Gàidhlig: bith (to be); tha (am/is/are), chan eil (am not/ is not/ are not), a bheil (am?/is?/are?), nach eil (am not?/ is not?/ are not?).
So, where most other European languages will change the verb slightly depending on who is doing it, Gaelic changes the verb depending on whether it’s positive or negative, stating or questioning. It’s not really an infinitive, it’s a Gaelic infinitive. There’s a difference. You know who it is by using a noun, or a pronoun such as mi, thu, e, i, sinn, sibh, or iad directly after tha and before the other verb.
Another thing about Gaelic is that you can’t have something. It’s got to be at you, or on you. Mostly you use aig (at) for this – agam (at me), agad (at you), aige (at him), aice (at her), againn (at us), agaibh (at you), aca (at them).
Here are a few examples of using this:
I have a pen and a book = Tha an leabhar agus an peann agam (Are the pen and the book at me).
I write with my pen = Tha mi a’ sgrìobhadh leis an peann agam (Am I at writing with the pen at me).
Do you speak Gaelic? = A bheil an Gàidhlig agad/agaibh? (Is the Gaelic at you?).
I speak Gaelic = Tha an Gàidhlig agam (Is the Gaelic at me).
I don’t speak Gaelic = Chan eil an Gàidhlig agam (Is not the Gaelic at me).
I wear a coat = Tha an còta orm (Is the coat on me).
I go to school with my sister on Monday morning = Tha mi a’ dol do ‘n sgoil leis an phiuthar agam anns a’ mhadainn Di-luain (Am I at going to the school with the sister at me in the morning Monday).
Anyway, that’s just the very basics of a little bit of Gaelic grammar, as I understand it thus far in my studies.