たぶんもう始まっているよね

N5 もう mou already / more N5 ている te iru be doing

N4 始 shi / haji.meru, -haji.meru, haji.maru commence, begin, commencer

N5 〜ている te iru Indicates ongoing action, continuous state, repeated habit, or resulting condition depending on context N5 〜もう mou Indicates recent completion or change, equivalent to already, shows action completed before now N5 〜も mo Means also, adds another similar item, often replaces particles such as wa ga or o N5 〜ね ne Sentence ending particle seeking agreement, softens statement, similar to right or isnt it N5 〜よ yo Sentence ending particle adding information to listener, emphasizes statement, expresses certainty or warning