The mother tongue is the language in which people learn to speak. In Galicia, the majority of people still learn to speak in Galician, although nearly half the population learns to speak in Castilian or in both languages. Nearly all of the older generation said their first words in Galician. This is however not the case amongst younger people. There is also a great difference depending on where one lives within Galicia. In general, it is in the villages and in the coastal areas that more and more people learn to speak in Galician while this is not the case in cities and inland areas. A decrease in the number of people who learn to speak in Galician has been observed over the last few years, and more and more people are now being brought up as bilingual speakers.
More than half the population learns to speak in Galician. Those who learn both languages make up a sixth of the population and the rest learn to speak in Castilian.
Fewer young people have Galician as their mother tongue and therefore larger numbers learn to speak in Castilian.
The number of speakers with Galician as mother tongue has dropped over the last eleven years, and the number learning both languages as children has risen.
According to the Instituto Galego de Estatística 2003 data, the mother tongue of the Galicians has primarily been Galician.
As can be seen, more than half the population learns to speak in Galician, which is followed by Castilian and those who learn to speak in both languages, which make up a sixth of the population. Very few people learn to speak in other languages because the number of immigrants that live in Galicia and speak a different mother tongue, other than Castilian or Galician, is scarce.
When undertaking an in-depth analysis of data, it is quite common to cross-reference the main variables with other variables of a sociological type. In this sense, it is interesting to compare the results according to the age of the interviewee, which permits us to see what intergenerational changes have taken place, and predict the possible situation in the future. The mother tongue according to age bracket in Galicia, gives the following results:
This figure clearly shows older generations of Galicians as the group that most learnt to speak in Galician. We can also see that as age decreases, fewer people have Galician as their mother tongue, and more people learn to speak in Castilian. The number of bilingual speakers from birth also appears to increase as age lowers, but this tendency changes in the last section (the under 16 age group). At first sight, there appears to be a strikingly clear general trend, of a loss of a large proportion of Galician speakers per generation but this appears to smoothen towards the end. We can thus conclude that fewer and fewer Galicians learn to speak in Galician. However, the number of those learning to speak in Castilian and in both languages simultaneously is increasing, and this tendency tends to stabilize among the youngest speakers.
The data can also be analyzed according to geographical criteria and we can see that there are differences between the two types of habitats (country and city for example) or between the coast and inland. Let us now analyze the results according to the administrative areas and groups of areas. On the one hand, we can distinguish the urban Galician areas, seven in all namely; Vigo, A Coruña, Ourense, Santiago, Pontevedra, Lugo and Ferrol. On the other hand, we can distinguish the following grouped administrative areas: Western A Coruña (A Barcala, A Barbanza, Bergantiños, Terra de Soneira, Muros, Fisterra, O Sar, Noia and Xallas), Eastern A Coruña (Arzúa, Betanzos, Eume, Melide, Ordes and Ortegal), Northern Lugo (Terra Chá, Central Mariña, Eastern Mariña, Western Mariña and Meira), Southern Lugo (Ulloa, A Fonsagrada, Os Ancares, Terra de Lemos, Chantada, Quiroga and Sarria) the remaining administrative areas in Ourense (Allariz e Maceda, Baixa Limia, Terra de Caldelas, O Carballiño, Terra de Celanova, O Ribeiro, Terra de Trives, Valdeorras, Verín, Viana and A Limia), Western Pontevedra (O Morrazo, O Baixo Miño, Caldas and O Salnés), and Eastern Pontevedra (Tabeirós-Terra de Montes, O Condado, Deza and A Paradanta).
The average figure for mother tongue is used to compare the mother tongue data between the different administrative areas. Such data results in a number that varies between 1 and 3, where 1 represents areas where more people have Castilian as their mother tongue, while 3 represents areas where more individuals learnt to speak in Galician. The results show five sections and are as follows:
As per criteria outlined above, we can see that there are three outstanding areas where the mother tongue tends to be Castilian. These are the areas where less people have Galician as their mother tongue and are comprised of the urban areas of Vigo, A Coruña, and Ferrol. The first two are the most densely populated places in Galicia, with important economic and industrial activity. In the following sections, we find the other urban areas of Pontevedra, Ourense, Lugo and Santiago. These are less densely populated areas and are less industrialized and more services oriented than Vigo and A Coruña. In this section we can also find the areas of Western Pontevedra, which are characterized by an important urban growth in the last few years (above all O Salnés and O Morrazo). In the last section, where a larger number of inhabitants have Galician as their first language, we find the rest of the non-urban areas, with two clearly distinguishable levels. The first level is made up of the non-urban areas of the province of Lugo, Ourense and those making up the so-called Eastern A Coruña. The second level includes areas in the provinces of Pontevedra and Eastern A Coruña where the greatest number of inhabitants speak Galician as their mother tongue.
If we compare the mother tongue of Galicians from a different source with recent data provided by the Mapa Sociolingüístico de Galicia (Sociolinguistic Map of Galicia) from 1992 , we can see the following evolution:
The trend for this period (11 years), is quite similar to the analysis performed using the age bracket. Although Galician is still the majority language, the number of those with Galician as their mother tongue has fallen. The group that has grown most is that of bilingual speakers. Numbers of people learning to speak in Castilian have risen slightly. During these eleven years, the number of speakers with Galician as their mother tongue has fallen while increasing numbers have learnt to speak both languages as children.
 IGE (2004) Enquisa de Condicións de Vida das Familias. Coñecemento e uso do galego. Ano 2003 (Survey on Family Life Conditiions. Knowledge and Use of Galician. 2003). Santiago, Xunta de Galicia.
 This work is published in three volumes by the Seminario de Sociolingüística da Real Academia Galega: Lingua inicial e competencias lingüísticas en Galicia (1994), Usos lingüísticos en Galicia (1995) and Actitudes lingüísticas en Galicia (1996).