正则表达式获取字符串中的所有英文字母字符

I have a string like this:

متن آزمایشی Demo Text 4 1.0.5 – متن آزمایشی

I want to grab only the English text "Demo Text".

I used this regex [a-zA-Z] but it's only getting the first letter of the text.

[a-zA-Z ]+

try this

preg_match_all('/[a-zA-Z ]+/sm', $text, $result, PREG_PATTERN_ORDER);
$result = $result[0];

This regex should work for you:

([a-zA-Z]+(?: [a-zA-Z]+)*)

RegEx Demo