A man of words and not of deeds, is like a garden full of weeds.

Bulgarian
Голям залък лапни, голяма дума не казвай.
Translation: Take a big bite, don't say a big word.

Easier said than done.

French
Mieux vaut faire que dire.

German
Leichter gesagt als getan.

Italian
Tra il dire e il fare c'è di mezzo il mare.