Paul Pimsleur (1928 – 1972) was an authority in the field of applied linguistics. He taught French phonetics and phonemics at the University of California, Los Angeles after obtaining his Ph.D. in French and a master's degree in psychological statistics from Columbia University. After leaving UCLA, Pimsleur went on to faculty positions at Ohio State University, where he taught French and foreign language education. At the time, the foreign language education program at OSU was the major doctoral program in that field in the US. While at Ohio State he created and directed the Listening Center, one of the largest language laboratories in the United States. Pimsleur was later a Professor of Education and Romance Languages at The State University of New York at Albany, where he held dual professorships in Education and French. He was also a Fulbright lecturer at the Ruprecht Karl University of Heidelberg, and a founding member of the American Council on the Teaching of Foreign Languages. He did research on the psychology of language learning and in 1969 was Section Head of Psychology of Second Languages Learning at the International Congress of Applied Linguistics. His research focused on understanding the language acquisition process, especially the organic learning of children who speak a language without knowing its formal structure. For this, he studied the learning process of groups made of children, adults, and multilingual adults. The result of this research was the Pimsleur language learning system. His many books and articles had an impact on theories of language learning and teaching. In the period from 1958 to 1966, Pimsleur reviewed previously published studies regarding linguistic and psychological factors involved in language learning. He also conducted several studies himself. This led to the publication in 1963 of a coauthored monograph, Underachievement in Foreign Language Learning, which was published by the Modern Language Association of America. Through this research, he identified three factors that could be measured to calculate language aptitude: verbal intelligence, auditory ability and motivation. Pimsleur and his associates developed the Pimsleur Language Aptitude Battery (PLAB) based on these three factors to assess language aptitude. He was one of the first foreign language educators to show an interest in students who have difficulty in learning a foreign language, while doing well in other subjects. Today, the PLAB is used to determine the language learning aptitude or even a language learning disability among secondary school students. Dr. Pimsleur died unexpectedly of pneumonia during a visit to France in 1972.

Audio recordings of language programs—streaming—have an advantage over print or academic classes because hearing is how humans learn to speak. That is how we learned our native tongues, and how we effectively learn second languages. As babies, we listened to our parents speaking. In our hard-wired desire to communicate, we learned our native language by imitating them. According to linguists, babies begin by distinguishing basic syllables, and around 3 months, start to babble, making simple sounds (“ba-ba-ba” or “ma-ma-ma”). They also imitate the tonal changes of their parents’ language. By sixmonths, they can distinguish the sounds of their native language fromthose of foreign languages and begin to practice its sounds, intonations, and rhythms.Most children by the age of 1 year can say a few simple words, even if they aren’t clear on theirmeanings. At 18months, most children have a speaking vocabulary of eight to ten words. By 2, they begin forming simple sentences. And then language fluency begins to soar. In the early 1900s, European linguists proposed that language learning would be better if it were conducted in the target language. In this approach—called the Direct Method (or Natural Method)—all directions, explanations, and definitions are given in the language being taught. In a French class, French and only French is spoken or read. All grammar is learned inductively. While this method most closely imitates the way we learn our first language, it is difficult to teach and can be frustrating and discouraging to learners. Most audio-based language learning programs combine both native and target languages into talking phrasebooks.

The German language is a West Germanic language and one of the world's major languages. German is closely related to and classified alongside English and Dutch. Around the world, German is spoken by ~100 million native speakers and also ~80 million non-native speakers, and Standard German is widely taught in schools and universities in Europe. Worldwide, German accounts for the most written translations into and from a language In German linguistics, only the traditional regional varieties are called dialects, not the different varieties of standard German. Standard German has originated not as a traditional dialect of a specific region, but as a written language. However, there are places where the traditional regional dialects have been replaced by standard German; this is the case in vast stretches of Northern Germany, but also in major cities in other parts of the country. Standard German differs regionally, especially between German-speaking countries, especially in vocabulary, but also in some instances of pronunciation and even grammar and orthography. This variation must not be confused with the variation of local dialects. Even though the regional varieties of standard German are only to a certain degree influenced by the local dialects, they are very distinct. German is thus considered a pluricentric language. In most regions, the speakers use a continuum of mixtures from more dialectical varieties to more standard varieties according to situation. In the German-speaking parts of Switzerland, mixtures of dialect and standard are very seldom used, and the use of standard German is largely restricted to the written language. Therefore, this situation has been called a medial diglossia. Swiss Standard German is only spoken with people who do not understand the Swiss German dialects at all. It is expected to be used in school.

Dutch is a West Germanic language spoken by around 24 million people, mainly in the Netherlands, Belgium and Suriname, but also by smaller groups of speakers in parts of France, Germany and several former Dutch colonies. It is closely related to other West Germanic languages (e.g., English, West Frisian and German) and somewhat more remotely to the North Germanic languages. Dutch is a descendant of Old Frankish and is the parent language of Afrikaans, one of the official languages of South Africa and the most widely understood in Namibia. Dutch and Afrikaans are to a large extent mutually intelligible, although they have separate spelling standards and dictionaries and have separate language regulators. Standard Dutch (Standaardnederlands) is the standard language of the major Dutch-speaking areas and is regulated by the Nederlandse Taalunie ("Dutch Language Union"). Dutch is also an official language of the European Union and the Union of South American Nations. Dutch grammar also shares many traits with German, but has a less complicated morphology caused by deflexion, which puts it closer to English. Dutch has officially three genders, masculine, feminine, and neuter, however, according to some interpretations these are reduced to only two, common and neuter, which is similar to the gender systems of most Continental Scandinavian languages. The consonant system of Dutch did not undergo the High German consonant shift and has more in common with English and the Scandinavian languages. Like most Germanic languages it has a syllable structure that allows fairly complex consonant clusters. Dutch is often noted for the prominent use of velar fricatives (ch and g, pronounced at the back of the mouth), often picked up on as a source of amusement or even satire. Dutch vocabulary is predominantly Germanic in origin, considerably more so than English. This is to a large part due to the heavy influence of Norman French on English, and to Dutch patterns of word formation, such as the tendency to form long and sometimes very complicated compound nouns, being more similar to those of German and the Scandinavian languages.