Does AEM provides any in-built translation facility apart from using external connector like Lingotek?

AEM has inbuilt Translator tool and the dictionaries that you manage are for presenting component UI in different languages. If you want to translate page or user generated content, see

1. Translating Content for Multilingual Sites

//To automate translation workflows, you integrate translation service providers with AEM and create projects for translating content into multiple languages. AEM supports human and machine translation workflows.

2. Translating User Generated Content

Nice Blog post: How To Implement a Translation Connector in AEM? | TO THE NEW Blog