Teh is a common typo for the. This misspelling of the most common word in the (written) English language is so common that it is one of the words in the auto-correct lists of spellcheckers in popular word processing applications, such as Microsoft Word, OpenOffice.org Writer, or Corel WordPerfect.
In the online slang known as Leet, it is deliberately used in place of the, and often spelled with a numeral 3 in place of e. Teh and t3h are the traditional spellings of the in the phrase "ph33r t3h ..." (Fear the...).
Besides being an alternate spelling of the, teh also has grammatical properties not generally applied to the. It can be used with proper names, as in "teh John"; compare the usage of the definite article in Greek: ο Ιωαννης (o Ioannes), literally "the John". A similar usage comes from German, where the definite article is used as a specifier to modify the noun: "Der Johann", again literally, "the John", could be used to identify John, and not Phil, as the subject performing a certain action.
Furthermore, teh is sometimes used in front of a verb, turning it into a species of compound noun chain. The best-known example of this is the word suck. Thus, the phrase this sucks can be converted into this is teh suck; the word pwn can be similarly converted (teh pwn). The above phrases are primarily used by the gaming community, and often intended humorously.
In English, the can be used as an intensifier for the superlative form of adjectives; compare "that is best" and "that is the best." Teh has a similar use as an intensifier for unmodified adjectives, generally marking a sarcastic tone. For example, "that is teh lame" translates as "that is the lamest." This contrasts with the use of the in English to construct mass nouns from adjectives, as in "blessed are the meek," where the meek denotes a class of people who are meek, or perhaps teh humble.
In the Malay language, Teh means tea.
There: Enjoy your tea!