This is the 9052nd most frequent Japanese word.
混じっ
"混じっ" means "mixed" or "blended."
混じって is used as the continuous tense of 混じる, meaning 'to mix' or 'to be blended'.
彼は人ごみに混じって歩いていた。
He was walking among a crowd of people.
混じる is used as a standalone verb, indicating incompatibility to mix naturally.
水と油は混じることがない。
Water and oil do not mix.
混じって expresses the blending or merging of one sound with others.