This song is a nice little tongue twister but easy enough for young kids to accomplish with some practice. If you teach it to them slow and start to increase the tempo the will catch on quickly. It's a fun tune to perform and many older people know it from their childhood.
Lyrics
V1. Habia una vez un barco chiquito 3x
Tan chiquito, tan chiquito, no podia navegar.
V2. Pasaron una, dos, tres, cuatro, cinco, seis, siete semanas 3x
Y el barquito, tan chiquito, no podia navegar.
V3. Y si la historia no les parece larga 3x
Volveremos, volveremos, volveremos a empezar.