M. JORDAN: Ah, it’s a lovely thing to know a thing or two.

M. JOURDAIN: Ah, la belle chose que de savoir quelque chose.]

Molière (1622-1673) French playwright, actor [stage name for Jean-Baptiste Poquelin]

Bourgeois Gentleman [Le Bourgeois gentilhomme], Act 2, sc. 6 (1670) [Oxford (1979), 2.4]
    (Source)

Having finally been successful in learning something (his vowels) from the Philosophy Teacher.

(Source (French)). Other translations:

How fine a thing it is but to know something!
[tr. Baker/Miller (1732), 2.6]

Ah! how nice it is to know something!
[tr. Van Laun (1860?); The Citizen Who Apes the Nobleman, 2.6]

Ah! what a fine thing it is to know something!
[tr. Wormeley (1894), 2.6; Page (1908); The Tradesman Turned Gentleman, 2.6; Jones, 2.4]

It's so reassuring to know something.
[tr. Bermel (1987)]

Ah, how wonderful it is to know something!
[tr. Applebaum (1998)]

Oh, what a beautiful thing it is to know something!
[tr. Pergolizzi (1999), 2.5]

It's wonderful to know so many things!
[tr. Rippon (2001), 1.3]