The present dissertation set out to investigate how the linguistic environment affects speech perception. Three sets of studies have explored effects of bilingualism on word recognition in adults and infants and the impact of first language linguistic knowledge on rule learning in adults. In the present work, we have found evidence in three auditory priming studies that bilingual adults, in contrast to monolinguals have developed mechanisms to effectively overcome interference from irrelevant information in the speech signal. Preliminary results on toddlers indicate no differences in the recognition of mispronounced words between bilinguals and monolinguals. Additionally, knowledge about rules in the first language was shown to have an impact on general rule learning abilities, while we did not detect an influence of bilingualism in this process. In summary, we have found evidence for an impact of the linguistic environment on the processing of indexical variability in word recognition as well as on rule learning. Bilinguals seem to have adapted to increased variability in their daily speech environment. In addition, rule extraction from unknown language input was unaffected by those adaptations but influenced by linguistic knowledge. / El principal objetivo de este trabajo fue investigar cómo el entorno lingüístico afecta la percepción del habla. Con esta finalidad se exploraron los efectos del bilingüismo en el reconocimiento de palabras y el efecto de la lengua materna en el aprendizaje de reglas. Para ver los efectos del bilingüismo en el reconocimiento de palabras se realizaron tres estudios en adultos explorando el efecto de facilitación por repetición, que mostraron que las personas bilingües han desarrollado mecanismos que les permiten minimizar las interferencias que ejerce la información irrelevante en la señal del habla. Por otro lado, se realizó un estudio con niños pequeños cutos resultados sugieren que no hay diferencias en el reconocimiento de palabras mal pronunciadas entre niños pequeños bilingües y monolingües. Respecto al efecto del conocimiento lingüístico de la lengua materna en el aprendizaje de reglas, se mostró que tiene un impacto en las habilidades generales para el aprendizaje de reglas aunque no se ha detectó una influencia del bilingüismo en dicho proceso. En resumen, se ha mostrado que el bilingüismo minimiza los efectos negativos de la variabilidad en el reconocimiento de palabras. Los bilingües parecen haberse adaptado a una mayor variabilidad en su entorno de habla cotidiana. Por el otro lado, se ha visto que la capacidad para extraer reglas de una lengua desconocida no está afectada por estas adaptaciones si no que está influenciada por los conocimientos lingüísticos en la lengua materna.

Lately most investigations regarding Swedish students’ level in Spanish as a foreign language indicate that there is a notable gap in their linguistic knowledge. It is possible to give various explanations to this tendency, such as the capacity of the educators or the level of motivation the students have. These explications, however, does not explain the fact that this is a problem on a national level. In order to be part of the search to find a potential solution to this issue this investigation has been made with the intention of assessing whether the students truly learn what they are being taught, by means of a modified error analysis, in which there it has also been investigated what part of the Spanish language that seems to be the most problematic to learn for the students at a Swedish upper secondary school. Last but not least this study also attempts to look into the possible influences of the first language and the gender of the learners. The error analysis that has been used consists in a test that contains twelve sentences, of which six are incorrect. All the sentences were based on constituents of the Spanish language that had already been studied in class. The students who participated in this study, all of them at the first, third and fourth level in the curriculum established by Swedish National Agency for Education, where asked to identify erroneous sentences and correct them. In this paper it has been proved that the learners, in fact, have failed to learn a considerable part of what they have been taught. It has also been established that neither gender nor native language can be considered relevant factors in the students’ learning ability. As for the most difficult part in the Spanish language it has not been possible to identify a generalizable result, but a few errors that can be found in more than one of the investigated groups, and therefore point out vital problems in the acquisition-process, has been identified. In conclusion, this paper shows that the knowledge of the Swedish students need some improvement, especially when it comes to ensuring that the learners won’t keep making the same mistakes over and over again.