Evidentials: "sou", "you", and "rashii"

In Japanese, describing how things look, guessing, or conveying rumors requires choosing specific evidential suffixes. The three most common ones are ～そう (-sou), ～よう (-you), and ～らしい (-rashii). They reflect different sources of information and levels of certainty.

～そう expresses visual impression ("looks like", e.g., oishisou - looks delicious) when attached to adjective roots, or conjecture when attached to verb stems. When attached to dictionary verbs, it means hearsay ("I heard that"). ～よう (～よう です) represents reasoned conjecture based on personal observation or intellect ("seems to be"). ～らしい is used for hearsay from reliable sources, or to describe typical characteristics ("it appears that" or "typically behaves like").

A common mistake is confusing the two uses of ～そう (conjecture vs. hearsay). When saying "looks delicious," you drop the final i of oishii to get おいしそう; if you say おいしいそう, it grammatically changes to "I heard it is delicious." Another error is using ～らしい for direct visual evidence, which sounds unnatural because rashii relies on indirect evidence.