The aim of this paper is to address English ``fear``-derived lexemes of emotion language from the perspective of grammaticalization. The ``fear``-derived lexemes that concern us are adverbs such as awfully, dreadfully, fearfully, frightfully, hideously, horribly, panically, terribly, and adjectives such as afraid, awesome, dreadful, fearful, frightful, hideous, horrible, panic, scary, terrible, terrific, tremendous. The ``fear``-derived lexemes evolve into RL (Respect Lexeme), EM (Epistemic Modality), and DM (Discourse Marker). In the stage of RL, the ``fear``-derived lexemes are contentful. The stage of EM includes the emphatic marker (intensifier) and the evidential marker. The ``fear``-lexemes also function as the DM such as the exclamative marker, the politeness marker, the mitigator, and the pragmatic hedger. The grammatical development of ``fear``-derived lexemes in English verifies that English ``fear``-expressions provide theoretical implications of human emotion into linguistic conceptualization.