How to say in Czech: They speak Dutch fluently.

English
speak fluently.
Czech
Oni mluví plynně holandsky.
Do they speak Dutch?
They do not speak Dutch.
They do not speak Dutch very well.
They speak Dutch.
They speak Dutch very well.
They speak only a little Dutch.
Does anybody here speak Dutch?
Are they learning Dutch?
Are they learning Dutch on their own?
They are learning Dutch.

Czech phrasebook and translator with tens of thousands of sentences translated by humans. Czechslator is being developed by Michal Měchura. CREDITS Czechslator's sentence generation engine is partially based on Grammatical Framework. All Czech pronunciation is computer-generated using Microsoft Azure Text to Speech. When Czechslator cannot find a translation in its own database, it looks in the PanLex dictionary or obtains a machine translation from Microsoft Translator. PRIVACY Czechslator does not save any cookies in your web browser and does not collect personally identifiable data. Czechslator uses StatCounter for traffic analysis, configured not to save any cookies in your web browser and not to collect any personally identifiable data.