This is the 6958th most frequent Spanish word.
duolingo
"Duolingo" is not a Spanish word; it is the name of a language-learning platform.
In this sentence, 'Duolingo' functions as a proper noun referring to the language-learning application.
Duolingo es una herramienta educativa muy popular.
Duolingo is a very popular educational tool.
Here, 'Duolingo' is used as the subject providing support for language learning.
Estoy progresando mucho en mis estudios de francés gracias a Duolingo.
I am making great progress in my French studies thanks to Duolingo.
The word 'Duolingo' in this example refers to the usability and experience of using the application.