餅は餅屋。

餅は餅屋。

Every man to his trade.

餅(もち)は餅屋(もちや)。

Mochi wa mochiya.

餅 (もち、もちい、かちん、あも)

sticky rice cake

は (は)

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

餅屋 (もちや)

rice cake shop keeper; rice cake store (shop)

Readings: ヘイ、ヒョウ、もち、もちい

Meaning: mochi rice cake

Readings: オク、や

Meanings: roof, house, shop, dealer, seller