Bahasa Melayu is one of the two national languages of Malaysia
(the other being English
Literally, "Bahasa Melayu" means "Malay Language", although it is also referred to as "Malay", "BM" and colloquially shortened to "Bahasa" (although the latter literally translated simply means "language").
It is very similar to Bahasa Indonesia, and in recent years Malaysia and Indonesia have been working to unify the language. Indonesia was colonised by the Dutch, while Malaysia (then Malaya) was settled by the English, so although both use a Romanised script, BM has an English influence on spelling rather than the Dutch influence that Indonesian has.
In addition to the Romanised script, which is the most common, there also exists a script called Jawi. Jawi is derived from the Arabic script and is still in use. Prior to English occupation, Islam was introduced to Malaysia around the 13th century and there are many Arabic words and sounds in the Malay vocabulary.
Bahasa Melayu is almost totally phonetic, that is, a letter or letter combination always sounds the same regardless of the word it is in. This makes it an extremely easy language for English speakers to learn. Most modern words have been imported from English, although the spelling is usually "Malaysianised", that is, made phonetic.
For example, words that don't necessarily look like English words, in fact, are when pronounced using the Malay phonetic system:
Bas = Bus
Polis = Police
Basikal = Bicycle
Syampu = Shampoo
Ais Krim = Ice Cream
Imigresen = Immigration
Tuisyen = tuition
Of course, there is the occasional "false friend". Most notably, although "Ais" is fairly obvious ("Ice"), "Air" is actually pronounced "Eye - Yer" and means "water" ("Udara" is the Malay word for "Air"). The interesting reason is that, being a tropical country, ice is a relatively new invention, while water is not!
The other main difference is that in Bahasa Melayu, like Spanish, adjectives and adverbs appear AFTER the noun or verb. So "School Bus" would be translated "Bas Sekolah" not "Sekolah Bas".
Bahasa Melayu should not be confused with Malayalam, which is an Indian dialect related to Tamil.
See also: Counting in Malay