すもももももももものうち
Sumomo mo momo mo momo no uchi.
Plums and peaches are both kinds of peach.
6 tongue twisters
Japanese 早口言葉 train fast, even syllables and the small ya, yu, yo sounds: kyo, ryo, byo. Keep every syllable the same length, including the long vowels, and do not drop the small tsu.