On the basis of cognitive-functional approach the article aims to explore the use of English language units normally associated with particular cognitive contexts and specific grammatical word class in a new function, namely as a means of expressing the modal category of evaluation. The article discusses the existing views on particles and introduces the notion of the disguised illocutionary particle. The research methods used include contextual, cognitive and linguistic corpus analysis. The main focus of the paper is on the disguised particles positive and positively. Special attention is paid to the criteria of identifying the particles, their meaning and specific features of the cognitive contexts they are found in. The author argues that the class of disguised illocutionary particles has a capacity to grow as new words are added to it. The findings contribute to the field of cognitive semantics and show its advantages over the traditional approach to grammar based on classifications by parts of speech. The findings can also be applied to text linguistics, linguistic pragmatics and translation studies.