The emergence of the covid-19 pandemic and the measures that were put in place to contain it ‒ such as limiting social contact, use of masks or mandatory lockdowns, quarantines, and isolations – have led to substantial changes in individuals’ behaviours, routines, and practices. At a time when the consequences of implementing these measures are still being assessed in various sectors, it is particularly important to explore how they have shaped family practices and children’s language development in their early years of life. 

It is widely recognised that poor language development in the early years of life can compromise long-term learning, increasing the likelihood of school failure and limiting children’s participation. Thus, in March and April 2023, data were collected through parental reports, including 402 families with children aged between two and a half and three and a half years on the date of completion of the questionnaire, conducted online. This study was based on the following questions:

1. How does the language development of children who went through the pandemic in the first years of life compare with the language development of children who did not have this experience in the same period?

2. To what extent are factors related to the pandemic associated with children’s language development?

3. Are certain family practices related to children’s language development?

Language development was assessed by means of parental reports, using the Communicative Development Inventory-III (CDI-III), validated for the Portuguese population with data collected before the start of the covid-19 pandemic (Cadime et al., 2021). This inventory evaluates two dimensions: a) vocabulary (measured by the number of different words a child produces in his or her daily life, from a list of 166 words) and b) the syntactic complexity of the sentences produced (measured by the number of complex sentences or syntactic structures the child produces, from a list of 26 example sentences). The results were analysed by percentile intervals, and each interval was assigned a qualitative descriptor in order to facilitate interpretation, according to the following correspondence scheme:

• Percentile equal to or less than the 10th percentile: very low level of development

• Between the 11th percentile and the 25th percentile: low level of development

• Between the 26th percentile and the 50th percentile: medium-low level of development 

• Between the 51st percentile and the 75th percentile: medium-high level of development

• Between the 76th percentile and the 90th percentile: high level of development 

• Above the 90th percentile: very high level of development

The 10th percentile is widely adopted as the threshold value below which a child is flagged for presenting late language development. This percentile represents the 10% of the population with the lowest levels of language development, with reference to the child’s age group. Thus, it would be expected that 10% of the sample would be at this level of language development, but the data show that, in children who lived through the covid-19 pandemic, this percentage is much higher: 34.3% and 19.2% for vocabulary and syntactic complexity, respectively. In other words, the number of children with a very low level of language development is two to three times higher than expected. To put it another way, about 1 in 3 children has a very low level of vocabulary, and about 1 in 5 has a very low level of syntactic complexity, when the expected ratio would be only 1 in 10.

In this study, 204 of the children were infected with covid-19 (infection confirmed by any type of test), while 198 did not have a confirmed infection. Children who were infected with covid-19 have better levels of language development than their peers, both in terms of vocabulary and in terms of the complexity of the sentences they produce, regardless of their age. This result may reflect a higher level of socialisation of children who were infected in this period, as interaction with other people is associated with both a higher probability of infection and the promotion of language development. No effect of mask-wearing on children’s language development was found.

Research has shown that reading books has positive effects on language development in children of different ages. In this study, about 38% of families report reading books to their children between 1 and 3 times a week currently, and 9.5% report never doing so. The frequency of this practice did not vary substantially between the present day, the periods of lockdown, isolation, or quarantine, and the periods in which the measures to contain the pandemic were in force (but during which the children were not confined or isolated). However, in households with mothers with higher education qualifications, the frequency of reading books was significantly higher in all periods considered. 

In turn, a higher frequency of reading books to children, both now and during the pandemic, is associated with better levels of children’s language development and vice versa. In families that read to their children more than 12 times a week, 42.9% have a high or very high level of vocabulary and 46.4% have a high or very high level of syntactic complexity in the sentences they produce. In the group of children for whom parents report never reading books, 57.9% have a very low level of vocabulary and 31.6% have a very low level of syntactic complexity in the sentences produced. Despite these results, in this group, 7.9% and 13.2% of the children have a very high level of vocabulary and syntactic complexity, respectively. This suggests that, although reading books plays an important role in language development, there are additional factors involved in language acquisition.

In contrast to reading books, amount of exposure to television seems to have varied over time: today, children between the ages of two and a half and three and a half years watch television on average about 1.7 hours a day, compared to 2.3 hours a day during lockdown periods, even though, at that time, the children were younger. For the three time points studied, the number of hours that children watch television is significantly higher among families whose mothers do not have a higher education qualification. During lockdown, isolation or quarantine periods, the children in these families were exposed to about 3 hours of television daily. This number represents about one additional hour of daily television compared to children whose mothers have higher education. Despite this, no relevant association was found between the number of hours of television exposure and children’s language development.

Overall, the results of this study are worrying, in the sense that they point to the existence of a very high percentage of children with late language development, which may have negative implications for these children’s future learning. The fact that the percentage of children with a very low level of performance is higher in the group that was not infected with covid-19 suggests that limited interactions with adults and other children may be one of the factors that contributed to this result. A high level of education in mothers and a higher frequency of reading books over time seem to be important factors for a better language development, and these aspects should be considered in the design of intervention programs aimed at children in early and middle childhood and their families. 

Data collection was carried out online, which may have limited the participation of households with a lower degree of internet access and less mastery of digital skills. A second limitation is related to the fact that a previously validated family practices questionnaire for the Portuguese population was not used, since the existing measures did not cover the target age group of the study and dimensions of interest. Another limitation is that the proportion of mothers with higher education qualifications among the participants in this study is relatively high (about 60% of the sample). Although this number is not representative of the Portuguese reality, it is comparable to the study in which the percentiles for the CDI-III were established (Cadime et al., 2021), it being relatively common for studies in this area to have a bias derived from greater participation in scientific research by mothers of higher socioeconomic and sociocultural levels.

CADIME, I., A. L. SANTOS, I. RIBEIRO, et al. (2021): «Parental Reports of Preschoolers’ Lexical and Syntactic Development: Validation of the CDI-III for European Portuguese», Frontiers in Psychology, 12.

FEIJOO, S., A. AMADÓ, F. SIDERA, et al. (2023): «Language acquisition in a post-pandemic context: the impact of measures against COVID-19 on early language development», Frontiers in Psychology, 14, 1205294.

MURILLO, E., M. CASLA, I. RUJAS, et al (2023): «The effect of the pandemic on language development in the first two years of life», Revista de Logopedia, FoniatrÍa y AudiologÍa, 43(3), 100315.