Hi Nane, this is a common question. The table below answers this. It basically depends on the last letter or sound of the word. Most words are pronounced with NO EXTRA SYLLABLE/BEAT. The difference between 'T' and 'D' endings is next to nothing. ( e.g. helped = helpt / called = calld) but in both cases if you tried to switch it T for D, the sound would naturally still be the same. Imagine how close they are when you quickly say "Tada!" A full beat is only added with T & D endings. This is because it would be almost impossible to hear a "D" right after a "T" without the help of "id". Imagine trying to pronounce: Wantd or Addt. The most common mistake is giving the full beat to words that only need the half beat, which are the majority. I hope that answers your question. Happy studies to you!

In a word with 1 syllable, double the final consonant ONLY if the word ends in 1 vowel + 1 consonant, excluding w, x, y (e.g. stop - stopped/ slam - slammed/ ban - banned) . In a word with 2 or more syllables, double the final consonant ONLY if the word ends in 1 vowel + 1 consonant AND the final syllable is stressed (e.g. regret - regretted/ admit -admitted/ prefer - preferred).

The doubling of the consonant is a generally applicable rule based on pronunciation. It depends on how the root word is pronounced. As you may know, adding E to the end of a word can change the pronunciation greatly in English. Doubling the consonant signals that we do not want to change the way the way the vowel is pronounced. Therefore, it applies to the "short vowels" (but not the "long vowels") where the stress of the accent falls on the syllable in question. This is not limited to the second and third forms.