Walter Kasper on "legitimate inculturated forms"

In 2010, the seventh volume of the collected works of Cardinal Walter Kasper was published, focusing on his writings on the liturgy: Die Liturgie der Kirche [The Liturgy of the Church] (Herder, 2010). According to a review of this volume by David Grumett in Reviews in Religion & Theology 18:4 (September 2011) 626–629, in one passage

Kasper acknowledges the variety of beautiful rites still in use (Ambrosian in Milan and Mozarabic in Spain, as well as variations in Dominican and Carthusian friaries and monasteries) as legitimate inculturated forms, suggesting that the trend in recent decades towards a single liturgical blueprint worldwide will not be the final word on a unified liturgy (p. 69).

This insight could be an interesting starting point for further reflections on the relationship between communal identity and a proper liturgical use or rite. It may also be the case that the history of the development of proper liturgies for the regions and religious orders mentioned by Kasper may help shed light on the issue of inculturation in the contemporary church (cf. John Paul II's encyclical Redemptoris missio 52-54 (December 7, 1990) and the Congregation for Divine Worship and the Discipline of the Sacraments's instruction Varietates Legitimae (March 29, 1994)).