Just been looking into this type of attack lately. See below
Changing a single letter in a text to a character from a different language, particularly one that visually resembles the original letter, is a technique used in phishing attacks to deceive users. For example, hackers may substitute a Cyrillic "а" (which looks identical to the Latin "a") for the Roman letter "a" in a website's URL, potentially redirecting users to a malicious site that appears legitimate. This method exploits visual similarities between characters from different writing systems, such as the Latin and Cyrillic alphabets, to create deceptive web addresses. While this tactic is not directly related to leet speak, which involves substituting letters with numbers or symbols for stylistic or obfuscation purposes , both techniques aim to alter text in ways that can mislead or bypass automated filters.