In reply to visitor.

I still can’t find if possible to change the place where the tweet breaks

You can use blocks for that. If you want a paragraph of text to be separated into multiple tweets, split that paragraph into two by adding a heading block between 2 pieces of text, for example.

where could I modify o translate the “This thread can be read here” text of the last tweet..

You can offer translations for this string (and others) here:https://translate.wordpress.com/projects/wpcom/

Once your suggestion is approved, it will be immediately available to anyone using WordPress and Jetpack in your language.