「こんにちは、雨が降っている。」（こんにちわ・あめ・が・ふっている）[kon-nichi-wa a'meh-gah-foo.tte'iru] In English we say "it is raining," but what is "it?" In Japanese, the particle 「が」 describes self-reflexive phenomena, such as "rain raining," "clouds clouding," "snow snowing," because these phenomena cannot manifest without also exhibiting their characteristic behavior in unison. Thus, while we do say "it is raining" in English, in Japanese 「雨が降っている」 [a'me-ga-foo.te'iru] is quite literally saying "Rain rains." Anything that is echoed, hollered, emitted, acted out, or engaged from within an object on its own accord is most likely paired with the intransitive, self-reflexive particle 「が」 -- just as often as we use "it" in English, native Japanese speakers are using 「が」 to explain the same thing in a completely different way; where the locus is more centrally from the common heart of the phenomenon, and not as exclusively an observer witnessing from afar.