The ability to hear and manipulate phonemes plays a causal role in the acquisition of beginning reading skills.
https://pdfs.semanticscholar.org/b79b/fa1cd44f665011164a2fc6a9c84a229f864e.pdf
What is phonemic awareness?
Phonemic awareness is the ability to perceive individual sounds in words, hold sounds in order as you say them, and to manipulate sounds within a word.
It begins to develop around 3 to 5 years old and does not require any understanding of the alphabet. This makes it an ideal pre-reading skill to work on. Some children will develop better phonemic awareness once they learn the alphabet and the sounds that the letters make. Others will continue to struggle and can have issues with this skill as an adult.
Phonemic awareness has been shown to be a very powerful predictor of later reading achievement. In fact, it is a better predictor than more global measures such as IQ or general language proficiency.
https://www.semanticscholar.org/paper/Phonemic-awareness-helps-beginning-readers-break-Griffith-Olson/e7aec0a41da1bb3cf60865c169c18a164ac0f0e7
Why does phonemic awareness matter?
It is the single best predictor of becoming a successful reader. You might notice….Also, a student who has learned to read may still be struggling with phonemic awareness. Their reading may sound very labored or they wear out quickly when reading.
Reading and phonemic awareness are mutually reinforcing: Phonemic awareness is necessary for reading, and reading, in turn, improves phonemic awareness still further.
http://www.educationalleader.com/subtopicintro/read/ASCD/ASCD_323_1.pdf
How can I tell if phonemic awareness is an issue?
Switching sounds in words, mumbly speech, difficulty rhyming, fatigue when reading, labored reading.
Screener: https://www.heggerty.org/download-assessments-and-resources
How does phonemic awareness impact learning disabilities instruction?
People with dyslexia tend to have an enormous amount of difficulty with this skill. Anyone with sensory issues may have extreme difficulty with these activities and it is not recommended to pursue these activities at first, especially if you are working with people who have Down Syndrome or Autism.