You teach Russian or Spanish with phonics. You teach Chinese with whole-word. English needs a bit of both, since it is mostly phonetic. An on-demand approach to phonics works very well. The rules and exceptions are pointed out as mistakes are made. This avoids the boredom of drilling endless phonics rules and the long-term difficulty of whole-word. A common mistake with phonics is the accidental association of specif…
>> It is common, particularly in New England, to drop or add an "R". The dropping and adding of consonants is one of the defining aspects of many accents. It isn't really incorrect, just a mode of speech. Texas: "Readin." Canada/Nebraska: "Reading." UK: "Reading-g." (Really. Every BBC presenter does the double-G ing on everything-g.)
I've listened for this, and can't hear it. Are you saying that after the final ŋ, you hear a g sound? Or that you think the ŋ sound is lengthened?
Every text on English phonetics gives ri:dɪŋ as the RP pronunciation. Here's a transcript containing words ending in "ing": https://en.wikipedia.org/wiki/Received_Pronunciation#Spoken_...