@NoName I'm not a native speaker, but in my experience Japanese writing uses kanji for most semantic words, using kana only for grammatical and functional words. There's a reason kanji have stuck around even though kana are well-established: they're still used everywhere.

@NoName: The Japanese writing system uses kana for foreign words (or words recently borrowed from foreign languages) and for grammatical inflections. Native Japanese stems are written with kanji.

Thanks, this is actually very good answer! I like how you come up with a way they might not use letters like we do.

The DNA example doesn't work so well (or works as well as comparisons to binary), as protein sequence is determined by codons (a set of three DNA bases), so there are effectively 64 "letters" rather than four. example

@NoName Chinese does indeed use more characters, but to get a High School leaving certificate, a student needs full knowledge of around 2000 Kanji as well as all the Hiragana, Katakana and Romaji (Latin Characters). Oh, yes, I am literate in Japanese.

@ping I'd say it's more like there are four letters, and syllables of 3 letters (creating 64 possible syllables). Looking at the writing without understanding it, there is no way to know you are supposed to take three bases in order to decipher meaning. (And if you understand the content, why would you even be looking at the number of different symbols?)

@Jasper OP says that for binary they would have decoded it to ascii. I would therefore expect them to decode DNA to either codons or an amino acid sequence. If binary doesn't work for them as a simple alphabet, DNA shouldn't either.

@No Name I think the other comments have covered it well, but Kanji are not just used for "special occasions". They're used for verb stems, proper names, and most nouns. You don't get much past 3rd grade level without Kanji.

Japanese and Korean are no more complex than any other non-creole language. There are no "very complex" language. However, your point holds that they are equally complex yet are represented by very different writing systems

A more nerdy example: a computer from Earth uses only 2 symbols (0 and 1) in order to anything possible. So if the alien civilization is in any way similar to computers on earth, they would use only 2 "letters" to transmit any message.

Fluent Japanese speaker and translator here. Japanese consists of kanji (Chinese characters), hiragana, and katakana. Which is used has less to do with function and more to do with the origin and history of the use of the word. I could go into detail but just wanted to chime in and point this out.

@AzorAhai, I think it's extremely difficult to sustain an argument that Korean is no more complex than Pirahã.

@PeterTaylor On what grounds?

@AzorAhai, vocabulary, grammar, expressible ideas.

@PeterTaylor The only reason one might consider Piraha to be less complex is its supposed lack of recursion, which is controversial.

@AzorAhai, if you don't intend to interact with my answer then why ask the question?

@PeterTaylor You gave a very vague response. I assumed recursion was what you meant by "grammar, expressible ideas."

Although belonging to completely different families, Japanese and Korean posses striking similarities when it comes to morphology (suggesting a relationship on the distant past either via shared inheritance, substantial borrowing between them or another, common substrates or superstrates, or belonging to a sprachbund, etc.) Yes the point remains that one uses a complex multi-modal writing system and the other one uses an alphabet without either gaining or losing expression power with respect to the other.

@Mindwin please, don't say something like that around the unicode consortium people, they might take it as a challenge