An overview, for example:

XXX (native name [pronunciation in IPA]) is a language from the ABC language family spoken in Country1 and Country2 by the XYZ people. It is spoken by XX million speakers.

A description of the genetic classification of the language.

Probable history of the language. What language(s) it is derived from and when it started diverging from the ancestral language(s). Dates of movement of major groups of speakers, etc. Brief descriptions of important changes in the language, such as reduction of sounds or grammatical cases.

When creating sub-articles, use the formula History of XXX where XXX is the standard English name of the language. Avoid the bulkier format History of XXX language since there is no need for disambiguation in this case.

In what countries/regions the language is spoken, and how many people speak it there.

List which countries have this language as an official language or other special status.

List of varieties/dialects of the language. Major dialects with lots of information should probably have their own page.

Creoles and other languages that are derived from this language.

If there is a significant amount of information here, it is probably best to have a separate article on the phonology, called XXX phonology (eg Somali phonology). See Wikipedia:WikiProject Phonetics/Phonology template for a suggested structure.

If a separate page is not warranted, it may still be best to divide the information in this section into sub-sections following the structure on the above phonology template.

If there is a separate page, give a brief summary here, eg the number of consonant and vowel phonemes; important features such as phonemic use of tone or vowel harmony; and unusual or interesting features of the language's phonology.

A brief description of the writing system(s) used to write the language. Writing systems have their own page, so what's written here should just be a brief discussion of how this language makes any special use of the writing system and a link to all the writing systems used to write the language.

A general outline of the grammar of the language. Focus on what makes the grammar of the language unique compared to other languages, related as well as unrelated. Lists of each word class and their individual properties, as well as full-fledged inflection or conjugation tables, are probably best put in a separate article.

General description of the morphology of the language.

General description of the syntax of the language. What is the usual word order (SVO, SOV, VSO, etc.)? Theoretical descriptions, lists of example sentences, and explanations involving syntax trees are probably best put in a separate article.

This section should contain a discussion of any special features of the vocabulary of the language, like if it contains a large number of borrowed words or a different sets of words for different politeness levels, taboo groups, etc.

Some short examples of the language in the writing system(s) used to write the language. You might also include sound samples of the language being spoken. Avoid making lists of tourist phrases such as "hello", "goodbye" and "where's the lavatory?" since these do not represent the specifics of either grammar or phonetics particularly well.

Be sure to cite sources. Use these example styles and citation templates as a guide.

The first link should be the appropriate {{Interwiki}}, if such a thing exists.

Websites like Ethnologue, Language Museum, the Rosetta Project Archive, and Omniglot often have useful information on languages; if so, they should be provided in the external links.

The Ethnologue report for the language is far from authoritative and should only be used as a useful tool to start new articles. Ideally it should not be the only source. SIL International has in several cases made classifications that are at odds with the rest of the linguistic community as well as the speakers themselves. In certain cases the reports actually contain factual errors and should be fact-checked against other linguistic literature.

To cite Ethnologue, use the {{Ethnologue25}} (or later) template as follows:

*{{e25|code=xxx}}

replacing xxx with the ISO 639-3 code. If Ethnologue's name for the language is different from Wikipedia's, write:

*{{e25|code=xxx|label=XYZ}}

where XYZ is Ethnologue's name. Otherwise Wikipedia's name gets inserted by default.

Omniglot provides information about writing systems, not languages per se, and so is not appropriate for languages without a written tradition.

If there are reliable sources about when the language was first attested, consider adding the page to the relevant Category:Languages by time subcategory. If the language is extinct and there are reliable sources about when the language went extinct, consider adding the page to the relevant Category:Extinct languages by time.