“…Hence /f, s, h/ are the sounds that exist in both L1 and L2 phonological system (shared sounds) whereas the other six sounds exist only in the L2 sound system (non-shared sounds). While there is a fair number of studies on the production of English fricatives by L2 Thai learners (Brière & Chiachanpong, 1980;Burkardt, 2008;Chunsuvimol & Ronakiat, 2000Kitikanan, 2016;Kitikanan, Al-Tamimi, & Khattab, 2015;Richards, 1966;Roengpitya, 2011;Sridhanyarat, 2015Sridhanyarat, , 2017, the study of Pansottee (1992) is the only that was carried out to explore the discrimination of English fricatives and the effect of interstimulus interval on the sound perception of eight-year-old and six-year-old children. The stimuli in her study were three types: a phonemic sound pair (P), in which two sounds exist in L1 and L2 (/f/-/s/), a non-phonemic sound pair (NP), in which neither of the sounds exist in L1 (/θ/-/ʃ/) and phonemic and a non-phonemic sound pair (PNP), in which one sound exists in L1 and L2 and the other exists in L2 only (/f/-/θ/, /f/-/ʃ/, /s/-/θ/ and /s/-/ʃ/).…”