LyX ⇒ How do I rename the fixed strings like Abstract,LoF..

[Juanjo]

Why is "algorithm" the only word, which is still in English? Is this a LaTeX or LyX Error?

Because the algorithm environment is defined by means of the float package, so not automatically translated by the babel package. Look at the tex file, where you'll find the lines

Code: Select all

\newfloat{algorithm}{tbp}{loa}[chapter]
\floatname{algorithm}{Algorithm}