Do you need a teacher?

Depends…

having a teacher is a “real shortcut” to speak / use the language through “TARGET SETTING”.

a teacher can give you the basic – the essentials ( Yes, the right amount )

a teacher can definitely build up your confidence to speak / to try listening

a teacher can hold a co-work relationship with you so as to guide you / provide the right content to you / give idea on how to increase motivation / help you before you want to give up.

He or she can help you make sentence correctly and and help improve your accuracy and fluency.