Untreated hearing loss can impact on all aspects of life, from the development of speech and language, to education, career and social interaction. That is why an early diagnosis is important at any age, regardless of what hearing solution you choose.
Speech and language development
Children learn to speak by copying what they hear. A child will hear a sound or word, reproduce their own version, then correct themselves as their listening skills improve. This is also the way in which a child learns to use language. (Note that speech is the ability to make sounds, while language is the ability to understand and use these sounds to communicate.)
But if a child can’t properly hear how a word is spoken, or even how they are pronouncing it, they will find it difficult, if not impossible, to reproduce the correct sound. This, in turn, impacts on the ability to communicate with family, other children, and teachers.
Here are some of the ways that speech and language can be affected by untreated hearing loss:
Vocabulary develops more slowly in children who have hearing loss, widening with age if there is no treatment
Difficulty understanding words with multiple meanings such as ‘leaves’, ‘date’ and ‘right’ and words with abstract meaning such as ‘before’ or ‘after’
Problems understanding and writing long or complex sentences
Difficulty hearing word endings, leading to misunderstandings, communication problems and poor grammar
Problems hearing quiet sounds such as ‘s,’ ‘sh’ and ‘f’, affecting pronunciation
Speaking too loudly, at the wrong pitch, at the wrong pace or with poor pronunciation
Of course, if a child can’t hear properly – and doesn’t have the necessary support in place – they will miss what’s being said at school, impacting on their ability to learn and participate in class.
Research shows that the development of reading skills is slower in deaf children.  And, as reading is fundamental to education, that can create a barrier to academic achievement.
Government figures for 2009 show that deaf children in England were 43% less likely to do as well in their GCSEs than other children. In fact more than seven in 10 failed to achieve the government benchmark of five GCSEs at grades A* to C, including English and maths. 
People with severe and profound levels of deafness are four times more likely to be unemployed than the general population even at a time of low unemployment, according to research by Charity Action on Hearing Loss. 
The employment rate for people who identify ‘difficulty in hearing’ as their main health issue was 64% compared with 77% for those with no long-term health issue or disability.
People with a hearing loss tend to earn an estimated £2,136 per person per year less than those with no impairment, controlling for other factors, including age, education, and gender. 
Practical challenges include difficulty using the telephone, following group conversations, for instance in meetings, and lower productivity as the effort of listening becomes more tiring.
Evidence shows that people with hearing loss are more likely to be unemployed and, of those who are working, to earn less than people with no hearing impairment.
In children, an undiagnosed hearing loss will act as a communication barrier, meaning they are less able to make friends or join in with group activities and may feel lonely and isolated. In turn this can delay the development of social skills and affect self-esteem and behaviour. 
Meanwhile, people who develop a hearing problem as adults may become frustrated, irritable, embarrassed and avoid social situations, leading to loneliness and depression. 
Research shows that untreated hearing loss can impact on general health.
Even people with a mild hearing loss (25 decibels) are three times more likely to experience falls in old age, with every additional 10 decibels raising the risk by nearly one-and-a-half times. This is thought to be partly because people who can’t hear well might not have good awareness of their overall environment, making tripping and falling more likely. But it may also be because the strain of dealing with the effects of hearing loss on the brain reduces its resources for dealing with balance and safety.
Dealing with the effects of hearing loss can cause stress, which in itself can reduce immunity, meaning you may become more susceptible to colds, flu and other infections. 
Many studies have linked untreated hearing loss in adults with increased risk of depression, possibly because people become more isolated.
And while there’s a growing body of evidence that has confirmed a connection between hearing loss and risk of dementia in older people, it’s not yet known whether treating the hearing loss will reduce the risk of the disease.
 Arrowsmith (2014) Hidden Disadvantage: Why people with hearing loss are still losing out at work. Action on Hearing Loss.
 The Real Cost of Adult Hearing Loss: reducing its impact by increasing access to the latest hearing technologies. Archbold S. et al, The Ear Foundation (2014).
 Bidadi S, Nejadkazem M, Naderpour M. The relationship between chronic otitis media-induced hearing loss and the acquisition of social skills. Otolaryngol. head neck surg. 2008 Nov;139(5):665-70
 Gopinath et al (2012) Hearing-impaired adults are at increased risk of experiencing emotional distress and social engagement restrictions five years later. Age Ageing (2012) doi: 10.1093/ageing/afs058 First published online: May 16, 2012
 Lin, F. and Ferrucci, L., Hearing Loss and Falls Among Older Adults in the United States, Archives of Internal Medicine (2012; Feb 27) 172(4): 369-371
 Marsland AL et al. Stress, Immune reactivity and susceptibility to infectious diseases. Physiol Behav 77(4-5)711-715, 2002