Scope and objective This Recommendation defines features of the Specification and Description Language that extend the features of the Basic Specification and Description Language defined in [ITU-T Z.101] to comprehensively cover the abstract grammar of the language. A canonical concrete syntax is given to cover the abstract grammar. The abstract grammar defined in this document with the abstract grammar of the Basic Specification and Description Language comprehensively defines properties of the language except the details of data and expressions. This Recommendation also includes features for inheritance of types@ generic systems@ macros and the handling of the Universal Multiple-Octet Coded Character Set. Together with [ITU-T Z.100]@ [ITU-T Z.101]@ [ITU-T Z.103]@ [ITU-T Z.104]@ [ITU-T Z.105]@ [ITU-T Z.106] and [ITU-T Z.107]@ this Recommendation forms a reference manual for the language. Objective The objective of this Recommendation is to define features of the Specification and Description Language additional to those features defined for Basic SDL-2010 so that the abstract grammar of all SDL-2010 except data and expressions is defined. As well as completing the abstract grammar@ the features for the inheritance of types is added. The defined concrete syntax is a canonical form that closely matches the abstract grammar. While this makes it possible to use each of the features@ a separate Recommendation on shorthand notation provides additional concrete grammar that makes SDL-2010 more practical to use. Application This Recommendation is part of the reference manual for the Specification and Description Language. The part of the language defined by this Recommendation does not usually include shorthand notation or Model sections@ so that a model written using only Comprehensive SDL-2010 or Basic SDL-2010 is not as concise or as readable as one using the full language. Shorthand notation or Model sections in Comprehensive SDL-2010 are transformed into the canonical concrete syntax given for Comprehensive SDL-2010 or Basic SDL-2010 or the data and action language in SDL-2010.