What orators lack in depth, they give you in length.

[Ce qui manque aux orateurs en profondeur, ils vous le donnent en longueur.]

Charles-Lewis de Secondat, Baron de Montesquieu (1689–1755) French political philosopher

Pensées Diverses [Assorted Thoughts], # 828 / 1086 (1720-1755) [tr. Clark (2012)]
    (Source)

(Source (French)). Other translations:

What orators want in depth, they give you in length.
[ed. Taylor (1856)]

What orators want in depth, they make up to you in length.
[ed. Wood (1899)]

What orators want in depth, they make up for in length.
[ed. Harbottle/Dalbiac (1904)]

What is wanting in orators in depth, they make up to you in length.
[ed. Benham (1907)]

What orators lack in profundity, they will give you in length.
[tr. Dargan (1907)]

What orators lack in depth, they make up in length.
[ed. Jones (1908)]

What orators lack in depth, they make up to you in length.
[ed. Stevenson (1947)]