Speakman has left the club with immediate effect in the last 24 hours.
"I share the words of the owner,” Le Bris said ahead of Sunday's FA Cup fourth-round tie with Oxford United.
“Kristjaan was a huge contributor to the club development from League One to Premier League. That deserves huge respect.
“He was really important for me, especially at the beginning for my integration . . . a new language, new league, new players, new club. He helped me a lot.
"That's part of professional life. We had two windows working together, the first in the summer and the second in the winter.
“But on a daily basis, when you start in a new country, language is really key.
"It's not a direct translation. You have culture and nuances and he helped me a lot for that part, as a coach and with the connection with the players.”