"The class has already started."
This is a difficult one.
I think that the word 'has' in the English translation is telling. If you were simply to say 'The class already started' you would be correct.
By 'has started' it is emphasised that it has not only begun, but is currently in session.
じゅぎょうはもうはじまりました = The class already began.
While possibly not grammatically correct, the example sentence would be closest to 'The class is started'.
In this case where the verb describes a state instead of action, the continuous ending ている = the past tense ending た, so 始まっています＝始まりました
Not necessarily. If your friend sticks their head out from the classroom and tells you 「始まっているよ。」That would mean that class is starting, not started.
The "....te imasu" form describes the state of action. In this case, the starting is already underway and that is the way things stand as far as the statement is concerned. The translation could either be "is (start)ing" or "has (start)ed."
English verbs have tense (reference time of action) but Japanese verbs have aspect (reference a state of action as incomplete, complete or static). These categories do not exactly correspond.
"Hajimatte imashita" would mean (more or less literally) "was in a state of starting" or (in more natural English) "had started."
Hope this helps. If not, just ignore it.
Brice, those Kanji look right to be, but should もう go at the start? I feel like timing information almost always goes at the start? (E.g. yesterday etc.)
はじまり is a noun meaning 'the start'; 'the beginning'.
はじまって is the conjugation of はじまる・はじまります when followed by another verb or generally when it is modifying something else (not appearing at the very end of the sentence).
Both "hajimari" and "hajimatte" are renyookei forms that link verbs in series. There is no appreciable difference in meaning between them but there tends to be a closer logical relationship between the linked verbs when the "hajimatte" form is used. The relationship can be logically coordinate or subordinate with either form.
Sorry, I didn't realize that DL was also teaching that form of renyoukei.
Both hajimari and hajimatte can also be used as renyoukei, in bridging clauses.
I can't picture a verb directly following hajimari unless it was part of the next (separate) clause.