This is a case study of a person with three L1s -English and the Nigerian languages Nupe and Hausa -who started studying Japanese as an additional language in the UK at the age of 30.The study investigates the participant's production of pitch accent in their spoken Japanese, focusing on its accuracy, i.e. adherence to Standard Japanese norms, stability, i.e. the extent to which repeated words have the same accent type, and F0 realisation, i.e. the F0 peak location and rate of F0 fall.These are compared to the accuracy, stability, and F0 realisation of the accent types produced by 21 monolingual English learners of Japanese (Murads-Taylor, in progress;Taylor, 2012).Unlike the monolingual English learners, the English/Nupe/Hausa trilingual learner is shown to produce pitch accent that is highly accurate and stable.In addition, the acoustic data indicates that F0 peak location and rate of F0 fall could also be consistent with Standard Japanese norms.Although the participant is a trilingual learner of another language, this is not L3/Ln phonology research (Cabrelli Amaro, 2012).It is beyond the scope of this paper to consider which of the trilingual participant's L1s most affects their Japanese, and how this relates to factors such as typological distance or language status.No attempt is made to identify whether any of the learners L1s are more dominant than any other, nor how they interact with one another.Instead, this paper's significance lies in the fact that it demonstrates that it is, in fact, possible to acquire accurate and stable Standard Japanese pitch accent.This has implications for research on monolingual English learners of Japanese, who produce accent types that are inaccurate and unstable, even after four years of Japanese study, including a year studying abroad in a university in Japan (Murads-Taylor, in progress; Taylor, 2011a;Taylor, 2011b;Taylor, 2012).English speakers' difficulty acquiring pitch accent has been argued by the current author (Murads-Taylor, in progress; Taylor, 2011a;Taylor, 2011b;Taylor, 2012) to be due to pitch not having lexical function in English, combined with the effect of pitch accent having low functional load in Standard Japanese (Kitahara, 2001), and showing considerable dialectal variation (Kubozono, 2012).However, alternative explanations could be: insufficient Standard Japanese input (see Flege, 2009) or lack of explicit instruction (see Thomson & Derwing, 2015).This study on the English/Nupe/Hausa trilingual learner -who has never lived in Japan, studied Japanese with a L1-English speaking tutor in the UK, and did not receive explicit instruction on pitch accent -allows us to be more confident in attributing the monolingual English learners' difficulty to a linguistic cause: the difference between the English/Nupe/Hausa trilingual learner and the monolingual English learners is their L1(s), not input or instruction.And unlike English, which does not use pitch lexically, Nupe and Hausa, both of which are tone languages, do.