Can't make a 100% statement as ours is only in use once a year for 2 weeks. However, the reason for the installation is precisely the wind measurement and we have already had several years of good experience. We use it at an open-air cinema and install it at the top of the scaffolding to decide when we have to stop according to the structural calculations, etc.
It's also cool for us that we can connect it directly to Weather Underground so that we can access the weather data externally during the day, etc.
No, it does not appear to be possible to change the language. There is no reference to this in the operating instructions. You can find them on the following link: EFWS 2900 operating instructions
As far as I know, these wireless weather stations like the one I have are purely recording devices. Have a look at blinds/awning suppliers. They have such detectors on sale.
Overall, both weather stations are powerful, but the dnt WeatherScreen PRO offers additional functions such as indoor climate monitoring and extensive visualisation options.
The display is practically the base station (receives the data from the sensor, displays it and uploads it to the cloud) - without it, nothing works.
The app that comes with it is, in my opinion, only good for the setup.
It's best to configure the upload to WeatherUnderground and then use their app (or website). Other cloud weather providers are also supported in addition to WU (but I have only used WU so far).
The link between the station and the display is wireless. You do not need WIFI but if it is connected, the date and time will be updated automatically.