Recent scholarly work has focused on borders, both geopolitical and cultural, giving attention to border lives and identities. This article, which focuses on sociocultural practices, addresses what can be called border languaculture. With attention on the Texas-Mexico border in North America, the authors discuss three key features of hybrid practices on the US 'side': (1) code-mixing that has a strong rhetorical component; (2) crossborder continuation but transformation of 'traditional' forms and conventions associated historically with Spain and Mexico; and (3) creation of 'new' hybrid forms and cultural products that establish social affiliations and distinctions. These languacultural features support the central point of the article: that self-positioning in this borderland is characterized by the multiplicity, contradictions and syncretism now being labeled mestizaje. Although cultural change has often been explained through acculturation, the syncretic nature of these border practices is better explained through transculturation, which emphasizes mutual influences and shifting power relations.