<p>I'm discovering a simple solution for singular-plural keywords searches. I heard about stemming but I don't want to use all its features, only plural/singular transformation. The language is Dutch. Have looked at <a href="http://www.snowball.tartarus.org" rel="nofollow noreferrer">http://www.snowball.tartarus.org</a> before. Does anyone know the simple solution for singular|plural relevant searches?
Thanks in advance.</p>

Use a dictionary, a list of stopwords (those you don't want to singularize) plus the rules for the language. If you don't know Dutch then I cannot help you, but show you how it'd be done in Spanish, for instance:
Plurals end with s, if it doesn't then it's done
If it ends with s,
check if it's a verb or conjugation ending with s if it is one, then it's done (verbs could be added to the stopwords list)
if it's not a verb, remove s
if the word exists in the dictionary, done
if it doesn't remove the previous letter, and check it in the dictionary.
if it's still not there it's an exception you'll need to check manually to code in the exceptions (I cannot right now think of any, but they always exist :)
Of course this will not translate directly to Dutch.
In general stemmers are already done and provide most of what you need, why don't you want them?