Indigenous languages are the most difficult to learn.

The argument

Although their native speakers only make up around 6% of the world’s population, there are over 4,000 indigenous languages currently spoken today. However, even the most widely spoken indigenous language - Southern Quechua - is only known to around 6-7 million native speakers. The first major obstacle you would have to overcome to learn an indigenous language is finding a way to learn it; while there are plenty of programs and tutors available for more widespread languages such as English, Spanish, and French, most indigenous languages are concentrated geographically in smaller communities. Duolingo is currently the only language-learning software that offers lessons in two indigenous languages - Navajo and Hawaiian. Indigenous languages are highly unique and can be extremely complex in a number of ways, such as pronunciation, grammar, sentence structure, irregularities, etc. For example, the eastern Amazonian language Tuyuca uses evidentiality, meaning that it “requires verb-endings on statements to show how the speaker knows something”. Silbo Gomero, spoken in the Canary Islands, is a language composed entirely of whistles. Some of these languages are isolate, meaning that they have no known relationship to any other language; so, no matter what a person's first language is, they would have a lot of difficulty learning a language isolate. Lastly, many indigenous languages do not have a writing system; while indigenous peoples have worked with linguists in the past to develop a written form of their language, the form may not even be agreed upon by members of the community. For example, the Shoshone language has developed multiple separate writing systems mainly for this reason. It is much more difficult to learn a language orally when not completely immersed in that native environment - especially without the guidance provided by a concrete writing system.

Premises

Counter-arguments

Two different kinds of difficulty are run together. Scarce tutors, absent course materials and unsettled orthographies are facts about the resources available to a learner, not about the language; a structurally simple language with no teaching infrastructure would score as 'hard' on this measure, and a structurally forbidding one with abundant materials as 'easy'. If access is what is being measured, the conclusion is about the state of language pedagogy rather than about languages. The difficulty of a language is also relative to the learner. The institutional rankings used by diplomatic language schools are explicitly framed as difficulty for speakers of a particular first language, because the burden is a function of typological distance between two languages rather than a property one language possesses on its own. Several of the examples do not support the generalisation either. Evidentiality is not confined to small or remote languages — it is a routine feature of Turkish and Bulgarian, both widely taught. Silbo Gomero is a whistled register of Spanish rather than a separate language, so it is not an example of an indigenous language's complexity. Isolates include Basque and, on most accounts, Korean, which are studied by large numbers of learners. And 'indigenous languages' is a sociopolitical grouping of more than four thousand unrelated systems with nothing typological in common, so no generalisation about their difficulty can follow from it.

Rejecting the premises

[Rejecting P1] Scarcity of materials and tutors measures the resources available to learners, not the complexity of the language; that is a fact about pedagogy rather than about linguistic difficulty. [Rejecting P2] The features cited are neither confined to indigenous languages nor shared across them — evidentiality occurs in Turkish and Bulgarian, isolates include Basque, and Silbo Gomero is a whistled register of Spanish rather than a language of its own.