The fastest language in the world is Japanese, and here is why.
Equality of languages
Languages are supposed to be equally great in functionality, since good things from other languages can be learnt and bad things in the language can be abandoned, making languages equally useful while specializing for the requirements of their speakers.
Information rate of languages
The purpose of language is for communication, so if they are supposed to have equal functionality, their information rate, which is the product of information density and syllable rate, should be the same.
In reality, the information rate of languages are not absolutely the same, but at least similar, as shown in the table below. But notice that the functionality of language does not come purely from it, which will be discussed later.
Characteristics of languages
Languages normally have a relative information rate of 0.90 or more, with English the highest and Japanese the lowest.
The reason why English has such a high information rate are probably its simplicity of words and a moderate pronunciation speed, which makes it better than Mandarin overall. Unique words are often created in English to express a new concepts, while compound words may be used in other languages, making their differences in information density.
The slowness of Mandarin is due to its four tones, so words should be pronounced more clearly for listeners to recognize the tones, slowing down the pronunciation speed of Mandarin.
The reason why Japanese has the lowest information rate and fastest pronunciation speed is the same, which is its low information density. As language are similar in functionality, the low information density will be compensated by its fast pronunciation speed to make it comparable with other languages.
The low information density in Japanese is due to its limited number of syllables, since Japanese does not allow the existence of complex syllables. To make use of a smaller number of syllables, longer combination of syllables should be used for pronunciation of words so that the sounds of words can be distinguished. On the other hand, the simple syllables in Japanese can be recognized quickly, so the pronunciation speed of the speaker can also be faster.
Nature of language
Now let’s return to the discussion above, how languages can be equal in functionality, while having different information rate?
One important point to note is that language is the representation of our mind, and our minds are equal, thus languages should also be equal.
There are two aspects of languages, oral and written, combined to form the functionality of languages. Since languages have the same functionality, a language stronger in oral form will be weaker in written form, and it is actually the case.
English is weaker in written form, due to its incoherence in pronunciation and written form of words, so speakers need to pay more effort in reading and writing English. In contrast, other European languages spell as how it is pronounced, so they are better than English in written form.
The incoherence in pronunciation and written form of words makes all European languages the same in functionality, and Asian languages make another way to achieve a better written form, so that they are also the same as European languages in functionality.
Chinese and Japanese share the common writings of Kanji, which is a better written form. Kanji is used to represent a word, but it is recognized like pictures, while European words as recognized by letters. Thus, Kanji in Chinese and Japanese makes the recognition of written words more efficient than European languages.
The benefits of Kanji is more obvious in Japanese, due to their different information density. Chinese use Kanji in the way of one syllable one Kanji, since Chinese created Kanji. The only benefit from Kanji is the recognition of words in written form, which bypasses the slowness in oral form and is is faster than European words.
Kanji brings tremendous benefits for Japanese. Since Kanji came from Chinese, a language with high information density, a Kanji can compress Japanese words with long combination of syllables into one symbol, making the recognition of written words in Japanese much faster. The advantages of Kanji in recognition also gives Japanese a boost in written form.
Overall, languages are equal in functionality, since the determinant is the cognition speed of our mind.