Alignment

Players Handbook (page 22)

After generating the abilities of your character, selecting his or her race, and deciding upon a class, it is necessary to determine the alignment of the character. It is possible that the selection of the class your character will profess has predetermined alignment: a druid is neutral, a paladin is lawful good, a thief can be neutral or evil, an assassin is always evil.

House Rule

Alignments as described in the PH and DMG are not applicable. A choatic evil creature may do some lawful good action for their tribe. A neutral PC may kill a monster to save the party. It just doesn't add up. Players choose how to role play their character in a situation, and can choose to be honourable most of the time, but support a break in and theft for the purposes of the campaign.
Aligments therefore do not exist in terms of limitations, alignment languages, etc.
However, clerics and rangers should be mindful of either the association with their diety or with nature.