Spanish in the year 1400 would have sounded quite different from the modern Spanish spoken today. During that time, Spanish was still in the process of evolving from Old Spanish (also known as Old Castilian) into what is known as Middle Spanish. Here are some characteristics of Spanish in the 1400s:
Pronunciation: The pronunciation would have been different, with variations in vowel sounds and consonant pronunciation compared to modern Spanish. The letters "s" and "c" before "e" and "i" were pronounced differently, similar to the "th" sound in English. Additionally, there were distinct regional differences in pronunciation.
Vocabulary: While some vocabulary would still be recognizable, many words would have evolved or changed in meaning over the centuries. Some words used in the 1400s may have fallen out of use or become archaic in modern Spanish.
Grammar: The grammar of Middle Spanish differed from modern Spanish in several aspects. Verb conjugations, word order, and the use of pronouns were different compared to contemporary Spanish.
Given these differences, it would be challenging to understand Spanish as it was spoken in the 1400s without prior exposure or specific study of Middle Spanish. It would likely sound like a distinct language or dialect rather than something immediately familiar. Some individual words or phrases might be recognizable, especially if they have survived in modern Spanish, but overall comprehension would be limited.
If you're interested in exploring the evolution of Spanish, you may find it fascinating to study Old Spanish and Middle Spanish texts with the help of specialized resources or under the guidance of experts in historical linguistics.