English consonant clusters are usually difficult for learners. In 'changed' ([t͡ʃeɪnd͡ʒd]), we have a cluster of three consonants, including the affricate [d͡ʒ], which is a complex consonant.
The short answer is: replace the affricate [d͡ʒ] with [ʒ] and pronounce it [t͡ʃeɪnʒd]. [ʒ] is the sound at the end of the word garage, so it should be easy for you.
Preliminaries
The word 'change' starts with the sound [t͡ʃ] and ends in [d͡ʒ], both of which are complex consonants and are called affricates.
Affricates are complex consonants; they start off as plosives (stop) and finish as fricatives.
A plosive (or 'stop') is a consonant produced by completely blocking the air at a particular place of articulation. For instance, the sound /p/ at the beginning of the word pin is a plosive. It's produced by blocking the air completely at the lips and then suddenly releasing it with a big puff of air. /p t k b d g/ are plosives in English.
A fricative is a consonant which is produced by bringing together the articulators (organs which are involved in articulating the sound e.g. tongue, lips, alveolar ridge etc) to the point where the airflow is not quite fully blocked; there's enough gap for the airflow to escape, but the articulators are so close together that friction is created as the air escapes. English fricatives are /f v θ ð s z ʃ ʒ/.
Affricate is a consonant that is produced by blocking the air completely (as in plosive) and releasing it as a fricative. But it happens so quickly that we don't even realise as we articulate them. There are two affricates in English: /t͡ʃ/ (as in chin) and /d͡ʒ/ (as in jug).
/t͡ʃ/ starts off as /t/ and is released as /ʃ/ whereas /d͡ʒ/ starts off as /d/ and released as /ʒ/.
Let's move on to the original question.
Pronunciation of 'changed'
If you omit the /d͡ʒ/, you'll get chained, which is a completely different word. So how to deal with it?
If you look at its pronunciation: [t͡ʃeɪnd͡ʒd], you'll see that there are three consonants (including the affricate) at the end of 'changed'.
The affricate [d͡ʒ] is a single consonant, but more complex than other simple consonants. In order to deal with the pronunciation of the cluster [nd͡ʒd], you can think of the affricate [d͡ʒ] as two consonants; [d] and [ʒ]. Now if we break up the affricate in 'changed', we'll get four consonants: [t͡ʃeɪ n d ʒ d], here we have four consonants now ([n d ʒ d]).
If we omit:
- [n], we'll get *[t͡ʃeɪdʒd]: it's chaged which is incorrect
- [d], we'll get [t͡ʃeɪnʒd]: [ʒ] is the sound at the end of the word massage, if we omit it, it can still be understood as 'changed' and doesn't change the meaning at all (try it!). Most native speakers pronounce [ʒ] rather than [d͡ʒ] in clusters like this without realising it
- [ʒ], we'll get *[t͡ʃeɪndd]: ill-formed because it has *[dd] in the same syllable and English cannot have a geminated consonant within the same syllable (Phonotactic constraint). It's also incorrect
- ending [d], we'll get *[t͡ʃeɪndʒ]: it's 'change' and we need changed, so it can also be incorrect, however, some people do pronounce changed that way in some situations.
So the best way to deal with 'changed' is to follow option no. 2 in the above options. If you omit the [d] part of the affricate [d͡ʒ], everyone will understand and it doesn't change the meaning of the word. I'd say no one will even notice.
/t͡ʃ/ is the sound in chin
/d͡ʒ/ in jug
/ʃ/ in ship
/t/ in time
/d/ in date
/ʒ/ in vision (or German garage or French jour)
I've marked ill-formed or incorrect pronunciations with a preceding asterisk (*)