Radical 口

7 strokes

mouth 口 (5) + tooth 牙 (780a) = oh! 呀

At the end of a phrase, this character can take a neutral tone (see Character 143 for another example of this happening).

The dentist looks into the mouth, sees a colored tooth and cries, “Oh!” / The giant had tied colored yarn round the tooth when he was trying to pull it out.

Compare this with “swallow” (779a above).