The paper deals with the effects of prescriptivism on the Lithuanian language. The research includes one domain of language use – radio and television, and one aspect of language – lexicon, in the period between 1960 and 2010. The investigation is corpus-based and focuses on the use of words that are classified as “incorrect” by the Lithuanian norm-setters. The study is important both as a discussion of the impact of prescriptivism on language change in general, as well as of the indirect influence of media on language, since media can affect the symbolic evaluation of specific language forms.The paper consists of five chapters. The first chapter “Review of the research” discusses the theoretical assumptions and concepts needed for further analysis: it gives an overview of studies on the effects of prescriptivism conducted in Lithuania and elsewhere, presents the concepts of second-level indexicality and style, and outlines the key characteristics of media change in Lithuania that are relevant to the study. Studies on the success of prescriptivism do not give a definite answer as to whether prescriptivism works. Institutionalisation and a high degree of stigmatisation of the corrected language forms can be listed among the factors that increase its success; prescriptivism is likely to be less successful when the “forbidden” language forms are too convenient to be given up, or when prescriptivist rules are too complicated for lay language users and the rules contradict each other. In the case of media, the effect of prescriptivism is said to be weakened by media commercialisation.When applied to the analysis of non-standard words, first-order indexicality refers to situations when the non-standard forms are used as value-free instances of ordinary speech, in already established meanings; in these cases, the speakers are not aware that they are using “incorrect” forms. Second-order indexicality refers to cases when non-standard words are used for additional function, e.g., to express a speaker’s particular identity or to construct a certain (informal, friendly) speech style. The concept of style, referring to the social differences between individual speakers, is used to analyse the use of words in concrete situations. The paper gives an overview of three sociolinguistic concepts of style that are relevant in this study: style as a degree of formality (e.g., when the speaker accommodates to the formal context of the media and uses less non-standard words); as audience and referee design (e.g., use of non-standard words in programmes for young audiences); and as a speaker design (e.g., play with language by the programme host in order to construct a fun persona).In the study of non-standard lexis, it is important to account for certain features of Lithuanian media development, such as the Soviet period, which was characterised by the use of newspeak, and the commercialisation of the media in the contemporary period. Accordingly, the paper analyses the uses of incorrect words as a part of newspeak and their use for the entertainment-related purposes such as language plays in present times. The paper also addresses the transitory period of radio and TV development, which has features from both the previous and the later periods, as well as some unique characteristics of language use.The second chapter “Radio and TV speech in the prescriptive discourse” presents an analysis of the metalinguistic discourse on media speech produced by Lithuanian prescriptivists from the pre-war period up to now. The analysis shows how this discourse preserved the same dominant idea about media’s role in language standardisation. On the one hand, during this whole time, radio and television were approached as responsible for teaching listeners and viewers the “correct language”; on the other hand, simultaneously, the language of radio and television was perceived as failing to conform to the prescriptive norms set by the norm-setters. The huge societal shifts that happened during this time did not make a major influence on this discourse. It remained very stable during different periods of time. The social, cultural and political changes in society and the media were taken into account only by adjusting the argumentation – by presenting patriotic, moral, ideological or legal motives that were meant to justify the language prescriptions.The third chapter “Research methods and data” presents the Corpus of Radio and TV speech, the concept of non-standard words, and the sources of prescriptivist corrections used in the analysis. The corpus of radio and TV speech includes data from 1960 to 2011 and is constructed in a balanced way to represent the periods of Lithuanian radio and TV development (Soviet, transitory, contemporary), as well as programme genres (talk programmes, information programmes, journals/features/documentaries). The speakers are coded into six types: news reader/voice-over, talk show host, expert, celebrity, hero and vox populi. For the analysis, the non-standard words that are classified as “incorrect” in the normative tradition of the Lithuanian language were coded. These include old (mainly, Slavic) and new (mainly, English) loans, the so-called hybrid words (that have a borrowed part), semantic loans, translations, as well as some lexicalised uses of words and some lexicalised syntactic constructions. Two types of words are analysed – individual lexical words and functional words. The latter include various fillers and discourse markers, as well as pronoun constructions with tai (e.g. kažkas tai ‘some(body)’). Non-standard words were identified from older and present style guides, including the database of language corrections created by the State Commission of the Lithuanian Language.The fourth chapter “Change in the number of non-standard words: a quantitative analysis” investigates development of the use of non-standard words on radio and TV, as well as the frequency of usage of the non-standard lexical forms. According to the corpus data, the average frequency of non-standard words by one speaker is 17 per thousand words, which makes up about 2–3 “incorrect” words per minute. Non-standard discourse markers and fillers (9.8/1000 words) are used most frequently, whereas individual lexical words (5.6/1000 words) are much less frequent, and pronoun constructions with tai (1.6/1000 words) are rarer still. Closer analysis revealed that the only statistically significant change between the analysed periods (Soviet, transitory and contemporary) was a decrease of the frequency of non-standard lexical words in the contemporary period compared to the previous ones. The frequency of discourse markers/fillers and pronoun constructions with tai did not change. Regarding the speaker types, the uses of non-standard words decreased in those groups that are within easier reach of prescriptivism – news readers/voice-overs and talk show hosts. Also, to a lesser extent, in the group of experts. Those groups of speakers that are less likely to be subjected to language correction practices (ordinary people) did not seem to change their behaviour: the number of non-standard words in their speech did not decrease, on the contrary, a slight increase has been noticed. These findings confirm the effects of institutionalised prescriptivism. Regarding genres, non-standard words are least frequent in information programmes, which are mostly based on the reading of written texts. Lists of the most frequent non-standard words during the three periods overlap to a great extent, which means that despite prescriptivist practices, the most frequent non-standard words do not disappear from the air.The fifth chapter “Change in the functions of non-standard words: a qualitative analysis” investigates specific communicative situations of the usage of non-standard words and takes into account the media-related and societal contexts, as well as the stylistic and social functions of the corrected lexis. A common trait of the use of non-standard words during all periods, interpreted as the first level of indexicality, is the use of common, everyday vocabulary, most likely without being aware of the “incorrect” status of the chosen forms. Also, non-standard words are used as a part of professional language, in this case the speaker might be aware that he or she is using an ‘incorrect’ word, but chooses to use it nevertheless for convenience or because of its indexical value for professional identity. During all the periods, non-standard words are also used as indices of informal and authentic communication between close acquaintances; this function is performed by all types of the studied non-standard words, particularly old borrowings and frequent fillers.The study identified a few style- and social meaning-related uses of non-standard lexis that explain the choice of the corrected forms instead of the required equivalents. In the Soviet period, some non-standard words were used as a part of Soviet newspeak; old borrowings were used in references to the ideological enemies of Soviet rule, mainly the ones from pre-war Lithuania. In certain cases, these words were employed due to their stylistic value in an intimate and authentic discourse. The late Soviet period saw the first use of non-standard words as markers of informal communication. The use of non-standard words in the transitory period shows some of the functions from the Soviet period, e.g., they are used as an element of newspeak, albeit without the Soviet ideological value, or as expressions of informality. A particular feature of this period is the use of non-standard words as an index of live and authentic speech, which was not allowed during Soviet times, as a means of authentic communication, and the criticism and violation of Soviet taboos. The contemporary period is marked by a huge variety of functions of non-standard words. It brings in a number of new style-related functions of non