## 4 Discussion  
Results showed that the Japanfol CAPT tool led experimental group users to carry out a significantly large number of listening, perception, and pronunciation exercises (Table 1). With an effective and objectively registered 57% of the total time, per participant, devoted to training (102.2 min out of 180), high training intensity was confirmed in the experimental group. Each one of the subjects in the CAPT group listened to an average of 612.5 synthesized utterances and produced an average of 291.4 word utterances, which were immediately identified, triggering, when needed, automatic feedback. This intensity of training (hardly obtainable within a conventional classroom) implied a significant level of time investment in tasks, which might establish a relevant factor in explaining the larger gain mediated by Japanfol. Results also suggested that discrimination and production skills were asymmetrically interrelated. Subjects were usually better at discrimination than production (8.5 vs. 10.1 tries per user, see Table 1, #Tries row). Participants consistently resorted to the TTS when faced with difficulties both in perception and production modes (Table 1, #Req.List. row; and Tables 2 and 3, #Lis column). While a good production level seemed to be preceded by a good performance in discrimination, a good perception attempt did not guarantee an equally good production. Thus, the system was sensitive to the expected difficulty of each type of task. Tables 2 and 3 identified the most difficult phonemes for users while training with Japanfol. Users encountered more difficulties in activities related to production. In particular, Japanese learners of Spanish have difficulty with [f] in the onset cluster position in both perception (Table 2) and production (Table 3) [27]. [8]-[9] present similar results: speakers tended to substitute [9] by [s], but this pronunciation is accepted in Latin American Spanish [28]. Japanese speakers are also more successful at phonetically producing [l] and [r] than discriminating these phonemes [29]. Japanese speakers have already acquired these sounds since they are allophones of the same liquid phoneme in Japanese. For this reason, it does not seem to be necessary to distinguish them in Japanese (unlike in Spanish). Regarding the pre/post-test results, we have reported on empirical evidence about the significant pronunciation improvement at the segmental level of the native Japanese beginner-level speakers of Spanish after training with the Japanfol CAPT tool (Table 5). In particular, we used two state-of-the-art ASR systems to assess the pre/post-test values. The experimental and in-classroom group speakers improved 0.7[1.1 and 0.6][0.9 points out of 10, assessed by gASR|kASR systems, respectively, after just three one-hour training sessions. These results agreed with previous works which follow a similar methodology [8,30]. Thus, the training protocol and the technology included, such as the CAPT tool and the ASR systems, provided a very useful and didactic instrument that can be used complementary with other forms of second language acquisition in larger and more ambitious language learning projects. Figure 4: Correlation between the gASR (**left** graph) and kASR (**right** graph) ASR scores of the post-test with the CAPT score. Our specific-purpose kASR system allowed us to reliably measure the pronunciation quality of the substantial quantity of utterances recorded after testing different training models (Table 4). In particular, this ASR system proved to be useful for working at the segmental (phone) level for non-native speakers. We followed standard preparation procedures for the models, restricted to closed small vocabulary tasks, where the words were selected according to minimal pairs trained with our tool. In this way, what is novel is the fact that we started from a native pronunciation model and transferred it directly to Japanese speakers.