The convergence between Basque and Romance is now largely unidirectional, with Basque becoming more like Romance, but shared features suggest that Basque had historically a considerable influence on the emerging Romance varieties in southern France and northern Iberia. Similar phonemic distinctions and phonetic realizations are found in adjacent Basque and Romance varieties, and sometimes beyond. The phoneme inventories of Basque and Castilian Spanish are largely identical. The Romance influence on Basque is most visible in the lexicon, as over half of the words used in everyday speech are of Latin or Romance origin. While the Basque contribution to the Romance lexicon of common nouns has been much more modest, some Basque anthroponyms have become very popular beyond the Basque Country. The integration of Latin verbs into the Basque lexicon triggered and then accelerated the switch to a tense-aspect system modeled on that of Romance. Like Spanish, the Basque varieties in Spain distinguish between two ‘be’-copulas, and two ‘have’-verbs. Certain types of relative clauses and passive constructions replicate Romance models, and a Basque mediopassive can be systematically translated into a Spanish clause with the pronoun se. The default constituent order of Basque is verb-final, but dependent clauses are often found in post-predicate position, matching the order found in Romance. While sharing many features with Romance varieties across southwestern Europe, Basque is closest to Castilian and Gascon, the two languages with which it has a long history of bilingualism and localized language shift.