The difficulties result from all sorts of complex linguistic reasons, ranging from the mechanics of the tongue and throat to more simple explanations, such as a sequence of both either vowels or consonants or else of syllables. Whatever the reason it allows for someone fluent in the language to detect straightaway whether another person speaking it is germane or innate to that language.
For example, Cabeleireiro is the Portuguese word for a hairstylist or barber. What makes it hard to pronounce is the fact that “lei” and “rei” come together in the word and have a similar pronunciation like the “ay” in the word “lay”.
Następstw, the Polish word for consequence, features a cluster of four consonants so requires some preparation.
Serrurerie, the French word for locksmith, is tricky even for those highly skilled in phonetics to pronounce correctly.
Other words can be very long and need to be broken down such as Fünfhundertfünfundfünfzig, the German word for the number 555.
Chiacchierare, the Italian for to chat, may sound as it’s spelt but its pronunciation is very hard due to the tricky sounds of ‘c’ and ‘ch’ which are repeated twice in the word.
It’s all part of the fun and intrigue offered by the many languages of our wonderfully diverse continent.