Languages aren't crucial for your training as a monk unless you decide to train bargaining. However, if you want to understand what other players are saying then you should learn the languages. It is both courteous and polite to converse with players in their own language. Some players will take great offense if you ask them for help and then tell them you can't understand them.

Below is a list of languages and where you can learn them. This page was also mercilessly stolen from Morgan McLain's Rogue Alley. He gives a list of directions to each sage and each language they teach. All directions start from Praxis Square.

Nightmare's Languages:

Akkadian, Artrexcian, Avidryl, Ba'atezu, Dragonish, Drow, Elcharean, Eltherian, Ersi, Farsi, Goblinish, Kendrall, Koboldish, Loyavenku, Malkierien, Marghstar, Meditian, Nibelungen, Nymal, Plantish, Shangtai, T'linghan, Tangetto, Terrakarn, Treeish, Wulinaxin

Praxis Sage:
(3w, enter library, w)

Akkadian, Artrexcian, Avidryl, Elcharean, Eltherian, Ersi, Farsi, Kendrall, Loyavenku, Malkierien, Nibelungen, Nymal, Shangtai, Tangetto, Terrakarn, T'linghan, and Wulinaxin.

Frejheim Sage:
(9n, ne, 5e, 4s, enter gate, 2sw, se, 3s, 8e, s, enter rathaus, e)

Akkadian, Artrexcian, Avidryl, Elcharean, Eltherian, Ersi, Farsi, Kendrall, Koboldish, Loyavenku, Malkierien, Meditian, Nibelungen, Nymal, Shangtai, T'linghan, Tangetto, Terrakarn, Wulinaxin

Nairn Sage:
(9n, ne, 18e, ne, e, 2ne, n, ne, n, 2e, enter house)

Artrexcian, Dragonish, Elcharean, Eltherian, Ersi, Farsi, Goblinish, Kendrall, Koboldish, Malkierien, Nibelungen, Nymal, Plantish, Terrakarn, Treeish, and Wulinaxin.

Botania Sage:
(7e, enter forest, 4s, all east, 3n, e, ne, enter tree)Artrexcian, Avidryl, Elcharean, Eltherian, Ersi, Farsi, Kendrall, Koboldish, Loyavenku, Malkierien, Nibelungen, Nymal, Plantish, Shangtai, Tangetto, Terrakarn, T'linghan, Treeish, Wulinaxin.

Endor Sage:750 gold fee
(3s, sw, 2s, se, ask ellis to ride boat, (wait), 2n, 2w, ne, ask leifa to study)

Akkadian, Artrexcian, Avidryl, Elcharean, Eltherian, Ersi, Farsi, Kendrall, Loyavenku, Malkierien, Nibelungen, Nymal, Plantish, Shangtai, Tangetto, Terrakarn, T'linghan, Treeish, Wulinaxin.

Jorthax Sage:
(12w, sw, 5s, 4w, 3s, 2sw, 3w, 2n, 2w, nw, sw, s, 3sw, 8w, sw, 11w, 2n, ne, open door, enter hut)

Artrexcian, Avidryl, Dragonish, Drow, Elcharean, Eltherian, Ersi, Farsi, Kendrall, Loyavenku, Malkierien, Nibelungen, Nymal, Plantish, Shangtai, Tangetto, Terrakarn, T'linghan, Treeish, Wulinaxin.

Dark Praxis Sage: PLAYER KILLING AREA
(Wear a talisman of inversion in Praxis - 3w, enter library, w)

Artrexcian, Akkadian, Avidryl, Ba'atezu, Elcharean, Eltherian, Ersi, Farsi, Kendrall, Loyavenku, Malkierien, Nibelungen, Nymal, Shangtai, Tangetto, Terrakarn, T'linghan, Treeish, Wulinaxin.