Capitalization rules are different in English and Spanish. Spanish uses lesser capitalization than English. Today we talk about some such differences, key capitalization rules in Spanish, and what not to capitalize in Spanish.
What not to capitalize:
Nationality: In Spanish, even though names of countries or cities are capitalized, words derived from them – such as nationality and language are not capitalized.
Example: I am American = Soy americano
Languages: Similarly, names of languages are not capitalized in Spanish.
Example: Do you speak Spanish = ¿Hablas español?
Days of the week: Names of the days of the week use lower-case letters.
Example: Today is Monday = Hoy es lunes
Unless the word comes as the first word of the sentence, we never capitalize names of ‘days of the week’ in Spanish.
Names of months: Names of the months of the year are not capitalized either.
Example: Today is May 5th = Hoy es el cinco de mayo
Composition (Movies, Books) titles: In written Spanish, titles of movies, books, plays, etc. capitalize only the first word and proper nouns.
Example: Harry Potter and the Sorcerer’s Stone = Harry Potter y la piedra filosofal
Introductory titles: Titles (such as doctor, profesor, señor) are not capitalized in Spanish. However, common abbreviations (like Dr. for doctor) are capitalized.
Place names: Names of rivers, lakes, mountains etc. are capitalized, but the identifier (type of place) is not capitalized.
Example: In English we would usually say ‘I am going to see River Nile’. In Spanish, it would become ‘Voy a ver el río Nilo’. While we capitalize ‘Nile’ or ‘Nilo’ we do not capitalize ‘River’ or ‘río‘.
The name of most religions, their adjectives, and their adherents (proper nouns) are not capitalized in Spanish.
Example: Christianity = el cristianismo
Christian = cristiano
Muslim = musulmán
Ordinal numbers: When an ordinal number is used after a name, it isn’t capitalized.
Example: George the eighth = George octavo.
Note that we also skip the ‘the’ in such cases while translating to Spanish.
Hope these rules will help you write Spanish better!