The Tensor got a nice Chrissie present, in the form of Vox Latina, and in passing poses the question as to whether [ʁ] is a liquid. Dunno. Dunnisne? But it reminds me of a nice example of phonemic organisation (and/or orthography) potentially influencing perception.
In field methods earlier this year we occasionally mistook [ʁ] for an alveolar trill [r] (or the ‘flap’ which we are transcribing as [ɺ]). our consultant thought this was a bizarre mistake to make, as to him [ʁ] is not a rhotic. We pointed out that in German (at least in the dialect of the native speaker in our class) the regular realisation of is [ʁ], as in French. This also came up when we asked about ways to write ‘the three ‘r’ sounds’ – for our consultant, [ʁ] is just the voiced counterpart of [χ] and had nothing in common with [r] or [ɺ]. It’s true that /ʁ/ is occasionally a fricative rather than a trill, although the default realisation is the trill.
So I guess the answer depends very much on your orthography, and how the phoneme patterns in the phoneme system of the language.