Determining the most difficult language in the world is subjective and depends on various factors such as a person’s native language, their familiarity with other languages, the language’s grammatical rules, the complexity of the writing system, and the cultural nuances involved.

However, some languages are widely considered to be among the most challenging for non-native speakers due to their complexity and intricacy. Some of these languages are:

1. Mandarin Chinese: It has a complex writing system, four different tones, and thousands of characters that require memorization.
2. Arabic: It has a difficult grammar system, a unique writing system, and many regional dialects.
3. Japanese: It has three writing systems, including kanji, hiragana, and katakana, and complex sentence structures.
4. Hungarian: It has a complex grammar system, with 35 different cases and many irregular verbs.
5. Finnish: It has complex grammar and numerous cases, with 15 different cases for nouns and 30 cases for verbs.
6. Basque: It is a language isolate, meaning it has no known linguistic relatives, and has a complex grammar system.
7. Icelandic: It has a complex grammar system, with four different noun cases, and many words that are difficult to pronounce.
8. Navajo: It has a complex grammar system, and its verbs change depending on the speaker’s relationship to the subject.

Overall, every language has its unique challenges, and what makes a language difficult for one person may not be the same for another.