amemiku

The SEO Slugs 4 bbPress plugin removes common words like ‘a’, ‘the’, ‘in’ from post slugs to improve search engine optimization.
For example, when you publish a post with a title like this:
“What You Can Do Immediately For Higher Rankings”,
WordPress automatically assigns a long filename to your post, called a post slug:
/what-you-can-do-immediately-for-higher-rankings
SEO Slugs 4 bbPress plugin strips common words like “what”, “you” or “can” out of your post slug to make it more search engine friendly. With SEO Slugs plugin activated, the slug for our example blog post would look like this:
/immediately-higher-rankings
The slug is generated on saving a post (so you get a chance to look at it before publishing, and change it), or on publish. It won’t overwrite an existing slug. You can force a new slug generation by deleting the existing one.

SEO Slugs 4 bbPress

Removes common words like 'a', 'the', 'in' from post slugs to improve SEO.

texttheater

NOTE: recent WordPress versions already properly transliterate umlauts if the 
site language is German. In that case, German Slugs is no longer needed.
While creating a post or page, WordPress automatically suggests a permalink. If 
your permalink structure contains the %postname% tag, then the title of your 
post or page will be used, simplified by conversion to lowercase, replacing 
spaces with hyphens, removing certain punctuation characters and removing 
diacritics from latin letters.
Thus, by default, ä is replaced with a, ö with o, ü with u and ß with s (similar 
for capital letters). For German, the conventional transliteration is ä to ae, ö 
to oe, ü to ue and ß to ss (sometimes sz in Austria, this is not yet supported). 
This plugin makes your WordPress apply the conventional transliteration.
I wrote this plugin because manually correcting WordPress’s suggestions is a 
considerable hassle, especially if you decide to change the title afterwards.
<h3>Support</h3>
If you have questions or suggestions, contact me at poststelle ät texttheater döt 
net.

German Slugs

German Slugs properly transliterates umlauts and the letter ß appearing in titles for slugs (i.e. for pretty permalinks).

SEO Slugs 4 bbPress vs German Slugs