Language plugin: removing formatting is too tricky

[Wiktor Walc]

1. Start with

<span dir="ltr" lang="es">
El invierno pasado estuvo tan fr&iacute;o que literalmente se form&oacute; hielo en mi barba.&nbsp;
</span>

2. Apply bold to "invierno"

3. Select a part of text around "invierno" and click the "Remove format" button to remove formatting.

4. Result:

<span dir="ltr" lang="es">El</span> 
invierno 
<span dir="ltr" lang="es">pasado estuvo tan fr&iacute;o que literalmente se form&oacute; hielo en mi barba.&nbsp; </span>

The information about the language is lost, causing an unexpected result for the unaware end user.

Expected result: removing formatting should not remove the information about the language (just colors, bold etc.), just like removing formatting does not remove links from the content.