since stackexchange is becoming like reddit and wikipedia where unknown , behind the mask moderators run these sites like dictatorship, I have decided to add answers here.
Chanting and reading are different. Vedic Chanting has two parts - Tone and Recitation (Patha). It further has four different tones - Udatta, Anudaatta, Svarita and Deergha Svarita. Pathas are the styles of hymnal recitation.
So unless your are are well skilled in these and your pronouncination, enunciation is accurate, you are not supposed to chant. Chanting the same mantras in different way produces different effects, different vibrations. Many a times a slight difference in spacing, intonation, pronounciation, enunciation produces different meanings. So unless you are classically trained to chant these, one shall avoid it but can read them with sound without making a sound, silently.
Ex: Many in north india swap va & ba. Ravindranath tagore becomes rabindranath tagore.
Many in north india also swap ra & da. Bada aadmi ( in hindi: big man) may become bara aadmi while pronounciation.
some sounds done exist in some region and language. ಳ್ sound exists in kannada but not in tamil.
ja and ya interchange again in spanish and sometimes in sanskrit too. om namah shivaya becomes om namah shivaja. You should know when and how it changes and when it doesnt.You should know sandhis to understand this.
So unless you are certain that you dont have vaak dosha (speech impedement, speech inaccuracy in sounds, etc.,).
Some also have hereditory speech issue as below.
Also many tend to speek or pronunce words from one side of the mouth, ideally for every sound, your tongue should be using both (left and right) side of the mouth equally and proportionally.
How many bite our tongue when we pronounce tha (as in tantric)? Very few. Many people also have hissing sound when they speak, (especially with s, sha, shha) sounds, might be because of gap in their teeth. Anyone can sing prayers. Anyone can read mantras.
Chanting is restricted to those who are classically trained to do so without the above mentioned issues.