63 Because of the use of the mother tongue in the administration of the sacraments and sacramentals can often be of considerable help to the people, this use is to be extended according to the following norms: a) The vernacular language may be used in administering the sacraments and sacramentals, according to the norm of Art. 36. b) In harmony with the new edition of the Roman Ritual, particular rituals shall be prepared without delay by the competent territorial ecclesiastical authority mentioned in Art. 22, 2, of this Constitution. These rituals, which are to be adapted, also as regards the language employed, to the needs of the different regions, are to be reviewed by the Apostolic See and then introduced into the regions for which they have been prepared. But in drawing up these rituals or particular collections of rites, the instructions prefixed to the individual rites the Roman Ritual, whether they be pastoral and rubrical or whether they have special social import, shall not be omitted.
Source: Sacrosanctum Concilium (Vatican.va)