Child-specific:
- Pre-natal factors (i.e., stress levels of the mother, maternal infections etc.) (Fox et al. 2002)
- Birth complications (i.e., premature birth, induced delivery due to the child being overdue, umbilical cord difficulties, infections) (Fox et al. 2002)
- Male gender (Wren et al. 2016, Campbell et al. 2003, Eadie et al. 2015)
- The presence of acute otitis media (Fox et al. 2002)
- The presence of hearing impairment / grommet insertion (Wren et al. 2016)
- Concerns about the child's coordination (Wren et al. 2016)
- Concerns about the child's arm/leg movements at 2 years (Eadie et al. 2015)
- The use of a bottle as a dummy (i.e., pacifier) beyond 2 years (Fox et al. 2002)
- Weak sucking at 4 weeks old (Wren et al. 2016)
Speech and language specific:
- Parental concerns about speech at 2 years (Eadie et al. 2015)
- Limited vocabulary use at 2 years (Eadie et al. 2015)
- Difficulty with non-word repetition (Wren et al. 2016)
- Poor intelligibility to others at 38 months (Wren et al. 2016)
- Difficulty combining words at 2 years (Wren et al. 2016)
- Difficulty pronouncing sounds (Wren et al. 2016)
- Poor word morphology at 38 months (Wren et al. 2016)
Parent-specific:
- A family history of speech and/or language difficulties (Campbell et al. 2003, Eadie et al. 2015, Fox et al. 2002, Felsenfield and Plomin 1997, Lewis and Freebairn 1997)
- Low educational level of mother (Campbell et al. 2003)
- Low socio-economic status - measured through home ownership (Wren et al. 2016)
Protective factors:
- Personality factors (i.e., persistence/resilience) (Harrison and McLeod 2010*)
- Bilingual children: The use of other languages by parents and the child's proficiency in their home language (Harrison and McLeod 2010*)
* Harrison and McLeod (2010) have considered both speech and language impairment