Impact of Down Syndrome on Language and Communication

Down syndrome is a developmental difficulty due to a chromosomal error (or a problem with genes). All children with Down syndrome have some degree of learning disability and develop skills at a slower rate to other children. Delays in language based and learning milestones are evident around their first birthday. The language skills of children with Down syndrome tend to develop more slowly than for other children. Despite a wide range of individual differences, most children are late in saying their first words, their vocabulary grows more slowly than in ordinary children and although they use the same range of two- word phrases as all children, they have difficulty in mastering the many rules for talking in grammatically correct sentences. This leads to the speech of many teenagers and adults with Down syndrome being restricted to short telegraphic utterances (keywords without the function words, for example “went swimming Dad” rather than “I went swimming last night with my Dad”). They also tend to have difficulty in pronouncing words clearly. The combined effect of talking in telegraphic utterances and poor pronunciation often makes young people with Down syndrome difficult to understand, especially if they are trying to talk to strangers out in the community rather than to those familiar with them at home or in school.

Language development for children with Down syndrome

Children with Down syndrome develop more slowly than typically developing children, and language skills are an area of particular difficulty. In addition, some aspects of speech and language development are more delayed than others. This pattern is sometimes referred to as a profile of relative strengths and weaknesses. Spoken language is delayed relative to cognitive development –

•  Most children with Down syndrome develop spoken language skills more slowly than their non-verbal mental abilities. They have therefore been described as having a specific speech and language delay.

Good early communication skills –

• Most children with Down syndrome are eager to communicate and their early non-verbal communication skills are good. These include making eye-contact, taking turns in babble games, developing joint attention, and using gestures. Children with Down syndrome tend to use early gestures effectively, and continue to use them for longer than typically developing children.

Strength in learning vocabulary –

•  Children with Down syndrome will often learn to understand what early words mean (comprehension) at a rate that might be expected for their level of non-verbal understanding (cognition). However, they are usually slower to learn to say the words (production). Over time, they steadily learn the meanings of a useful range of vocabulary but production continues to develop more slowly than comprehension. Usually, children with Down syndrome understand more than they can say.

Weakness in learning grammar –

• Learning to understand and use grammar is an area of greater difficulty for most children with Down syndrome – developing more slowly than vocabulary. Many children make themselves understood by putting key words together without all of the appropriate grammar – for example, “me go school bus”, rather than “I go to school on the bus”. However, studies suggest that, while development is slower, young people with Down syndrome can continue to learn grammar and sentence structures through the teenage years.

Difficulties speaking clearly –

• Children with Down syndrome typically babble like other children. However, they do not move on to attempt to say words but tend to use more gestures for longer than other children with a similar level of understanding. This may be because children with Down syndrome find speech production and saying words more difficult.

Wide range of individual differences –

•  Studies of vocabulary development suggest that children progress at different rates, with some children with Down syndrome saying less than 50 words at 3 years and others over 300 words (though this variation is also true of younger typically developing children at the same cognitive level).

Same developmental order and pattern –

• Studies indicate that children with Down syndrome develop spoken language skills and learn vocabulary and grammar in the same order as other children. Similarly, studies have found the same links between spoken vocabulary size, combining words and developing grammar for children with Down syndrome as other children.

Why this pattern of speech and language development observed among children?

A number of factors probably contribute to the pattern of speech and language development observed among children with Down syndrome. These also provide some guidance for intervention.  Hearing loss –

• Many children with Down syndrome experience hearing loss in the early years and this has been shown to influence their spoken language development. Medical care guidelines recommend regular hearing tests for all children with Down syndrome.

Speech sound discrimination –

• Typically developing children can discriminate between the sounds in their native spoken language in the first weeks of life. Speech sound discrimination and production skills at around 7 to 10 months predict later progress in learning to use spoken words. There is no similar research into speech discrimination in children with Down syndrome in the first year of life. However, hearing problems are likely to influence the ability to discriminate between sounds, and this will affect a child’s ability to learn to understand words as well as to say them. For example, consider “cat”, “hat”, “mat”, “sat”, and “bat” – these are all early words with only one differing sound, but each has a different meaning. Even a mild hearing loss may make it difficult to distinguish between these words when spoken.

Storing spoken word patterns –

•  Studies suggest that children with Down syndrome may have more difficulty in learning and storing accurate sound patterns for words (phonological representations). This may influence their ability to discriminate between, and learn the meaning of, similar sounding words. It may also influence their ability to say the words accurately. It is possible that additional repetition and practice may help.

Cognitive delay –

• Children with Down syndrome generally develop and learn more slowly than typically developing children. They may find it more difficult to pick up word meanings from everyday conversations, and may need more exposure to words in order to link word to meaning. All children learn their first words from hearing them stressed as single words – not just in sentences.

Less input –

• There is some evidence that children with Down syndrome experience less conversation with their parents than other children. If they are not attempting sounds and words as often as other children, they may be talked to less often. If they are talked to less often, the children have fewer opportunities to learn words and to practice saying them.

Verbal short-term memory –

• Most children with Down syndrome have particular difficulties with verbal short term memory. Verbal short term memory is important for holding verbal information and influences word learning. A number of studies have shown a link between verbal short term memory and learning grammar and syntax. In contrast, visual spatial short term memory is a relative strength for children with Down syndrome.

Why Down syndrome people have problem in speech? Children with Down syndrome commonly experience feeding, swallowing and speech difficulties due to anatomical and physiological differences in their mouth area. These differences include a high arched palate, small upper jaw as well as low muscle tone in the tongue and weak oral muscles. Children with Down syndrome can experience a lot of oral motor difficulty which can cause speech and feeding problems. Down syndrome is characterized as a genetic chromosomal disorder that causes developmental and intellectual delays. Among the cluster of observable symptoms:

• Short stature
• Different facial structure
• Hearing loss
• Vision loss
• Gut/digestion issues
• Low muscle tone
• Thyroid issues
• Atlantoaxial Instability (AAI), cervical spine abnormalities
• Intellectual disability
• Holes in the heart
• Sleep issues

Children with Down syndrome don’t necessarily have every single one of these, and there are others, but these are perhaps the most common and well-recognized. Each of these issues can affect speech. The four main ways they impact speech ability are: Structure, Tone, Cognition and Sensory Issues.

• Structure. Specific to speech, it should be noted that the shape of the child’s head and face overall is different. The middle of the face, nose, mouth and upper jaw are smaller. In turn, that means there is less room for speech. It can also impact the airway and require a person to be more precise to have the same level of clarity as a typically-developing person. The palate too is taller and narrower, which means the person has to move their tongue further to make accurate speech sounds. There are also structural differences in the tonsils, teeth and ears. For children with Down syndrome, their ears may sit a bit lower than the typically-developing person, which means they are more prone to stuffiness, frequent ear infections and hearing loss. Sometimes this is seasonal, so hearing loss can be temporary or permanent. Nonetheless, it can impact speech.
• Tone. Note: This is not about how strong a child is. Instead, it refers to how their muscles respond to gravity. Typically, a person can have their mouth closed while at rest and breathe through their nose. Children with Down syndrome, however, might have their mouth open at rest because of tone issues. In turn, this results in mouth-breathing as well as low tongue posture – both of which can make speech more challenging.
• Cognition. Most kids won’t pick up a new sound or word on the first try. They need to hear it several times. For a person with Down syndrome, however, they’re going to need more practice. Whereas a typically-developing child might need to hear a new sound two-to-six times, a child with Down syndrome may need to hear it 20 times.
• Sensory. There are two kinds of sensory issues: Hypo-aware and hyper-aware. Hypo-awareness means they cannot register sensory impact as easily (it’s why they might constantly be putting things in their mouth). Hyper-aware means that sensory input that might not bother most kids can really bother a person with Down syndrome.

Combining all these challenges, it is almost guaranteed that children with Down syndrome are going to have a speech delay. It simply is going to take them more time to develop sounds from the very first stages. It also makes them more likely to suffer a speech sound disorder. A significant percentage of the population with Down syndrome has difficulty in speech production for life. They can show signs of both stuttering and cluttering. People with Down syndrome are born with an extra chromosome as a result of a genetic accident before or around the time of conception. This results in a certain degree of learning difficulty which can affect the ability to understand and produce speech and language. One of the biggest problems for many people with Down’s syndrome is the unintelligibility of their speech to others. Unintelligibility and dysfluency often go hand-in-hand. People with Down syndrome may find some or all of these steps particularly difficult. Ideas may not be clearly formed; the language plan and/or the speech movement plan may not be well established; the actual process of speech may be a problem. As well as this, hearing loss, which is quite common in people with Down’s syndrome, makes learning and understanding language difficult. Also, the individual may lack the social awareness needed to know when or where it is appropriate to say what is being thought. For all of us it is common to find that, as the pressure to speak and speak well builds, a breakdown in fluency may occur. Imagine that you are trying to plan what to say in a foreign language—one where you only know a few words! You are likely to have long pauses when you are thinking of words; you might start a word, realize it’s wrong and try another word; you may repeat a word a number of times while you are trying to plan the sentence. In fact you may appear very dysfluent! For a person with Down’s syndrome, wanting to convey messages through a system that does not always work perfectly may lead to:

1. Repeating whole words or parts of words while trying to think of the next bit of the sentence (it’s…it’s…it’s big)
2. Long pauses in the middle of the sentence when he or she can’t think of what to say next (it’s a………ball).
3. Pauses in unusual places in sentences, often followed by two or three words in a sudden rush that may be hard to understand (I’m going swim……mint’omorrow). This stop- and start speech can be caused by problems in the language program or in the conversion of the language into a speech muscle program. The effect is as if the “bottled up” air is escaping from the lungs in a rather uncontrolled fashion. Fluent speech is dependent on a steady flow of air.
4. Emphasis being placed on the wrong word in a sentence or on the wrong part of the word. This may occur because the language program is not precisely planned or the control of movements of the speech muscles is not sufficiently well organized (I like to eat apples).
5. Some struggling to find the right speech sounds to start the word off (a…er…er.i…er…um…over there). Sometimes it may be difficult for the person to start the voice working leading to sudden high pitched or loud sounds. 6. Possible problems with hearing others and/or with noticing that what has been heard has not been understood. This may lead to hesitant and unsure speech and to communication between the person with Down’s syndrome and the listener breaking down.

It is possible that fluency depends on an equal balance between demands made on the language system and the abilities of the individual to meet these demands. Stuttering may occur when demands exceed one’s abilities Co-morbidity is also more common among children with Down syndrome. They are more prone to be diagnosed with childhood apraxia of speech (a motor speech disorder). We also sometimes see a condition called dysarthria (another motor speech disorder sometimes described as sounding like one has “marbles in the mouth”). All of these can result in speech impairments beyond just a simple delay – and it can be even more difficult if your child has an additional diagnosis of autism spectrum disorder or epilepsy or suffers setbacks due to surgery recovery. Despite these difficulties children with Down syndrome are keen communicators but require some encouragement and training to help them do so in an effective manner. Speech and language therapy is therefore recommended to help facilitate this desire to communicate and can be quite a beneficial form of therapy.