Why do English characters require fewer bytes to represent than other alphabets?

One of the first encoding schemes to be developed to use in mainstream computers is the ASCII (American Standard Code for Information Interchange) standard. It was developed in the 1960's in the United States.

The English alphabet uses part of the Latin alphabet (for instance, there are few accented words in English). There are 26 individual letters in that alphabet, not considering case. And there would also have to exist the individual numbers and punctuation marks in any scheme that pretends to encode the English alphabet.

The 1960's was also a time where computers didn't have the amount of memory or disk space that we have now. ASCII was developed to be a standard representation of a functional alphabet across all American computers. At the time, the decision to make every ASCII character to be 8 bits (1 byte) long was made due to technical details of the time (the Wikipedia article mentions the fact that perforated tape held 8 bits in a position at a time). In fact, the original ASCII scheme can be transmitted using 7 bits, the eight could be used for parity checks. Later developments expanded the original ASCII scheme to include several accented, mathematical and terminal characters.

With the recent increase of computer usage across the world, more and more people from different languages had access to a computer. That meant that, for each language, new encoding schemes had to be developed, independently from other schemes, which would conflict if read from different language terminals.

Unicode came as a solution to the existence of different terminals, by merging all possible meaningful characters into a single abstract character set.

UTF-8 is one way to encode the Unicode character set. It is a variable-width encoding (e.g. different characters can have different sizes) and it was designed for backwards compatibility with the former ASCII scheme. As such, the ASCII character set will remain to be one byte big whilst any other characters are two or more bytes big. UTF-16 is another way to encode the Unicode character set. In comparison to UTF-8, characters are encoded as either a set of one or two 16-bit code units.

As stated on comments, the 'a' character occupies a single byte while 'ա' occupies two bytes, denoting a UTF-8 encoding. The extra byte in your question was due to the existence of a newline character at the end (which the OP found out about).

1 byte is 8 bits, and can thus represent up to 256 (2^8) different values.

For languages that require more possibilities than this, a simple 1 to 1 mapping can't be maintained, so more data is needed to store a character.

Note that generally, most encodings use the first 7 bits (128 values) for ASCII characters. That leaves the the 8th bit, or 128 more values for more characters . . . add in accented characters, Asian languages, Cyrillic, etc, and you can easily see why 1 byte is not sufficient for keeping all characters.

In UTF-8, ASCII characters use one byte, other characters use two, three, or four bytes.