Speakers of the same language make characteristic errors when pronouncing a particular foreign language, and those errors form strictly specific system. That is the system of errors i.e. the third system which is generated by the interference of any two language systems, in this case, Croatian and German. Since the aim of this paper was to make a system of errors at a phonetic level, it was necessary to compare the phonemic inventory (consonant and vowel) and accentuated system of both languages so to see what do these two systems have in common and what differentiates them. What they have in common should not cause any problems to the native spakers of German when prononuncing the Croatian language, or the errors should not appear as a result. On the other hand, what distinguishes these two systems will most likely be the cause of the errors. A survey was conducted after the description and comparison of these two different systems. For this purpose, six participants were recorded while reading a short text written in the Croatian language. An analysis followed and its results showed that the native speakers of the German language who are learning the Croatian language mastered well the vocal and consonant system of the Croatian language, with the exception of certain voices, and did not quite master the Croatian accentuation, which is not surprising given the fact that it differs greatly from the accentuation in the German language.. Also, a somewhat lower percentage of assimilation has been achieved, which suggests that the initial assumptions have been largely confirmed.