Nope, it's just something Japan brought in to take into account foreign words with sounds their own alphabet doesn't cover. Same principal as フェ、ファ、フォ which account for sounds introduced in foreign words (obviously these would be へ、は、ほ in Japan's alphabet, ふ being the only one that uses the 'f' sound). The small ぁ after the つ simply modifies the sound to tsa instead.
Nope, it's just something
Nope, it's just something Japan brought in to take into account foreign words with sounds their own alphabet doesn't cover. Same principal as フェ、ファ、フォ which account for sounds introduced in foreign words (obviously these would be へ、は、ほ in Japan's alphabet, ふ being the only one that uses the 'f' sound). The small ぁ after the つ simply modifies the sound to tsa instead.