What is single word or phrase/idiom for "someone speaks alot but works very-very slow" [duplicate]

What is single word or phrase/idiom for "someone speaks a lot but works very very slow" for example.... someone said/planned he would do 100 task but actually finished less than 10 task

Solution 1:

All talk (and no action)

Much discussion but no action or results

"Don't count on Mary's help—she's all talk"

"Dave has been saying for months that he'll get a summer job, but he's all talk and no action."

This idiom may have begun life as all talk and no cider, which Washington Irving cited as an American proverb in Salmagundi (1807). However, similar sayings antedate it by many years—for example, “The greatest talkers are always the least doers” (John Ray, English Proverbs, 1670).

Solution 2:

There is a proverb says,

I hear cracking, but I don't see grinding.

It means that someone speaks a lot, but does nothing.