With over 50,000 characters and tones that can completely change the meaning of a word, Mandarin Chinese is considered one of the most challenging languages to learn.
Arabic has a complex grammar system and its writing system is completely different from English, which can make it difficult for English speakers to master.
Japanese has three writing systems and a complex honorific system that changes the way you address people based on their social status.
Finnish has a complex grammar system and long words, and it is not part of the Indo-European language family, making it quite different from other European languages.
Hungarian also has a complex grammar system, and it uses suffixes instead of prepositions to indicate tense, case, and possession.
Icelandic has a complex grammar system and a large number of declensions and conjugations, making it difficult to learn for non-native speakers.
Russian has six cases, which can make it difficult to understand sentence structure, and its Cyrillic script is also different from the Latin alphabet used in English.
Korean has a complex honorific system and a unique sentence structure, which can take time for English speakers to get used to.
Basque is not related to any other language in the world, making it difficult to learn for speakers of other languages. It also has a complex grammar system and long words.
Navajo is a tonal language, and its complex grammar system has a number of irregularities that can make it difficult to learn.