When you learn your first language, you do not learn the structure, grammar, and mechanics; you only learn how to speak it. Many native speakers have difficulty understanding the structure of their own language because it is something that is so natural to them and they do not have a frame of reference. However, when language students learn a second or third language, they are often taught the grammatical structure and the mechanics of the language. These skills can help people better understand how their own native language functions.
Better Grasp of Written Language
In order to be a better writer in your native language, you need to be aware of the grammatical and mechanical structures, like prepositional phrases and verb tenses. Many native speakers are more familiar with the spoken version of their language rather than the written version, so native speakers often make many mistakes. But, when they learn the grammatical structures of their second language, they begin to see the same structures in their own language.
Learning the Parts of Speech
If English is your first language and you begin to learn Spanish, you will need to learn how to conjugate verbs in Spanish. You will then begin to see how the conjugated verbs in English work. English also has many rules regarding sentence structure, like not ending sentences with a preposition. So, when you learn about prepositions in Spanish, you are then able to apply that new knowledge to English and you will no longer end sentences with prepositions. This will improve your writing ability in your own language.
Access to More Languages
Once you have spent a few years with a second language, you will find that learning languages becomes much easier. For example, if you begin learning Spanish, you will find that other Romance languages like French, Portuguese, and Italian are much easier to learn. Many words have the same roots. For example, the words for “you’re welcome” are very similar. The French say, “De rien.” The Italians say, “Di niente.” The Spanish and Portuguese say the same thing, “De nada.”
Word Decoding Skills
Many native English speakers do not realize that their language is full of words that have been taken from other languages. Once the Normans invaded in 1066, the English began borrowing/stealing words from languages and English speakers continue to do so to this day. When native English speakers learn new languages, they realize where many words come from and they have an easier time figuring out new words.
Many people struggle with decoding new words while reading. Learning a new language opens up a brand new vocabulary strategy by being able to connect root words from the new language to words in the native language.