Confidence is a skill, build it one word at a time.

Confidence is not innate, it’s a skill. And in language learning, it’s built one word, one risk, one success at a time.
Make someone’s efforts feel seen and celebrated.
Make a big deal, use it to model your expectations and good practice, don’t take anything for granted.
Start your lesson and aim to “Catch someone being good”. But go beyond the generic praise, be specific, make someone really feel seen and share with everyone:

-“What I really like about what you said was...”
-“Class, did you notice how she used........That was so great!”
-“Did you all hear that beautiful, smooth pronunciation? Amazing, if I didn’t know you, I’d think you were French”
-”What he did right there was a perfect example of...., that’s what we want to use”

-”I want to draw your attention on that fabulous piece of work because…”

Provide personalised feedback to make students feel seen, avoid generic praise. 
Make someone feel like they are leading by example....and you have noticed and appreciate it.
Everyone loves being a good role model. Create good role models in your classroom. 
Many students fear speaking a new language because mistakes feel public and risky. Create a culture where efforts are celebrated and noticed. Your classroom is a safe place.
Use the Target Language to praise and model the use of the language you teach, in a natural situation.
Re-use all the opinion phrases and adjectives which you teach to praise students (Also when marking books) All throught the lesson.
Familiar phrases used in a natural way makes it more relevant for students and increases their self efficacy leading to an increase in motivation (The Self Determination Theory, Ryan and Deci)
Confidence is the stage on which competence can appear. You want to increase motivation? Focus on making students feel competent, always. Every successful attempt, no matter how small, is a step towards fluency. Confidence is contagious, confidence is a skill. Build it one word at a time, and you’ll open the door to a lifetime of communication.