Spanish as a language is known to have developed in the 8th and 9th century. Spanish is said to have developed as a dialect of Latin in northern Spain. Then it spread to other parts of the world where Spanish colonies developed, especially the Americas. Based on this Spanish historical languages can be broadly classified as Romance languages (those which originated in Rome). The other major romance languages are Latin, French, Italian, Portuguese and Roman.
The Spanish historical languages are further classified as:
Castilian: This is the standard Spanish. The Spanish used till the 15th century is termed as old Spanish and that in the 16th and 17th centuries is referred to as classical Spanish. Castilian Spanish developed after the Roman Empire declined.
Mozarabic: Between the 14th and 15th centuries Iberian Peninsula was ruled by Islamic conquests. During this period and after the Christian rule was re-established, Castilian Spanish was greatly influenced by Moorish Arabic (Arabic spoken by Christians in the Moorish territory). This gave rise to the Mozarabic dialect of Spanish which is one of the oldest dialects in Spanish historical languages.
Judaeo-Spanish: This is the Jewish influenced Spanish spoken by the Jewish communities worldwide. The Jews who were expelled in the late 15th century settled elsewhere and carried their Jewish and Spanish vocabulary along. The language has a strong Greek influence to it and is now spoken outside Spain.
Catalan: Is a cross between French and Spanish. Also called as Valencia, it is spoken in many provinces of Spain – Andorra, Catalonia, Valencia and Balearic Islands.
Galician: This Spanish language began developing very early in Galicia province of Spain. S it borders Portugal and was once invaded by Germanic people, the language shows a distinct influence of Portuguese in it.
Basque: This is a form of Spanish that is spoken by the ethnic tribes of Spain. The language has a distinct western European influence to it, especially French. But Basque is now a dwindling tribe with most of the originals having migrated to the Americas. However, Basque is spoken by about 26% of the population in Navarra province of Spain.
Other Spanish languages include: Aranese, Asturian, Aragonese, Cantabrian and Extremaduran These are spoken by a minor population in Spain and restricted to small pockets of the country.