Which high frequency word includes an irregularly spelled word?

The high frequency word that includes an irregularly spelled word is "of." This word is categorized as irregular because it does not follow typical phonetic spelling rules, making it difficult for beginning readers to sound out or decode. Instead, it must be learned through memorization as a sight word.

In contrast, the other options provided, such as "home," "mind," and "tree," can be sounded out phonetically based on standard spelling patterns and rules. For instance, "home" features the silent 'e' at the end that modifies the vowel sound, but it remains phonetic. Similarly, "mind" and "tree" can be decoded without breaking any phonetic rules. This differentiates "of" as the unique choice among high frequency words due to its irregular spelling.