There are many ways of classifying Mayan languages, and in general the more sources you consult the more confused you will get (presumably at a certain point the confusion arc reverses). The thing to know is that there are a lot of them (31 is a number often given, but sources range all the way from 21 into the 50s) and they are for the most part mutually unintelligible (with differences that can be as great as those between German and English, say). Among the Mayan words to enter English are cacao and cocoa (kakaw) and shark (xook). For information on Proto-Mayan and the origin of the Maya people, see this page. The following system (based on that of Terrence Kaufman and Lyle Campbell) breaks things down into five major subgroups:
Chol is spoken in Chiapas, Chontal in Tabasco. There is an unrelated (non-Maya) group confusingly called Oaxaca Chontal.
Southern Guatemalan lowlands near Copán. Their language is closest to that of the Classic Maya. 52,000 speakers estimated in 1995. A closely related language, Ch'olti, is extinct.
Sometime around 150 CE a proto-Cholan group muscled into the Yucatec area. Some of these later moved to highland Chiapas and developed into Tzeltalan. Today these are the main Maya of the Zapatista movement.
Chiapas, 265,000 estimated speakers in 1995
2. Huastecan (Waxtekan)
Veracruz and San Luis Potosi, Mexico. The Huastecans are the only major Maya group separated from the main culture. They have adopted many aspects of the culture of their Mexican neighbors. The closely related language Chikomuceltek is extinct.
Chujean (Chuj, Tojolabal)
Kanjobalan (Kanjobal-Jacaltec: Jacalteco, Kanjobal), Moch
These languages are spoken in Chiapas and Northern Guatemala
about 18,000 speakers (1998) in western Huehuetenango department of Guatemala.
Ixil (Chajul, Cotzal, Nebaj)
estimated 71,000 Ixil speakers in 1995.
Mamean (Mam, Tacaneco, Tectiteco)
The Mam capital was Zaculeu. In Guatemala, they now live around Huehuetenango. 500,000 speakers in Mexico
Kekchi (Q'eqchi' in the new orthography)
Widespread from Alta Verapaz to Lago Izabal; also Belize and El Salvador. 363,00 speakers total, 1995.
Pocom (Poqomam)The Poqoman center was Mixco Viejo; now live near Guate and Jalapa. 31,000 estimated speakers in 1995.
Iximché was the center of their culture. Now live around Lago de Atitlán and Sololá.
The Achi live in Baja Verapaz. 58,000 estimated speakers in 1995.
The western highlands Quiche (K'iche' in the new orthography) is the culture of the Popul Vuh. Their name means "place of trees," and it is transformed through Nahuatl and Spanish into Guatemala. 925,000 speakers estimated 1995.
Long-time inhabitants of Santiago Atitlán area. 80,000 estimated speakers, 1995.
SacapultecoAbout 37,000 speakers in the Quiché department of Guatemala
SipacapenoAbout 6,000 speakers in the San Marcos department of Guatemala
UspantecAbout 3,000 speakers in the Quiché department of Guatemala
Southern Peten and Belize
Yucatec is the language of the builders of Chichen Itza. 700,000 speakers estimated 1995. They call themselves Maya, from which the name for the larger civilization was drawn.
Spoken by fewer than 1000 people total (lowland jungles of Eastern Chiapas).