In English, some words contain silent letters. A silent letter means a letter that we don't pronounce when saying a word. Let's have a look at one example: Listen (t is the silence letter here). Therefore, we shouldn't pronounce the "t" when saying "listen".
“A” as a silent letter:
Logically
Critically
Musically
Physically
"B" as a silent letter:
Bomb
Climb
Debt
Doubt
Dumb
Lamb
Numb
“C” as a silent letter:
Disciple
Science
Scissors
Ascent
Fascinate
“D” as a silent letter:
Bridge
Handsome
Grandson
Sandwich
Wednesday
"E" as a silent letter:
Make
Dine
Excite
Single
Debate
Desire
“G” as a silent letter:
Design
Foreign
Sign
Reign
Campaign
Align
"H" as a silent letter
Ghost
Honest
Hour
What
When
“N” as a silent letter:
Autumn
Column
Damn
Solemn
Condemn
"K" as a silent letter:
Knife
Knew
Knight
Knock
Knee
"L" as a silent letter:
Walk
Talk
Could
Should
"T" as a silent letter:
Butcher
Castle
Listen
Match
Often
Christmas
Whistle
Fasten
Hustle
Moisten
“U” as a silent letter:
Guess
Guest
Guide
Guilt
Guitar
League
Vague
Guard
"W" as a silent letter:
Whole
Answer
Sword
Wrist
The words containing the silent letter are pronounced always without that silent letter no matter which tense it is.
So we would pronounce "listen" and "listened" in the same way when we are focusing on the silent letter.
However, you have to be careful, don't generalize.
Because "t" is silent in "listen", it doesn't mean all the other words containing "t" is silent.
There are only specific words where silent letters exist.