can diphthongise
Regular verb: diphthongise - diphthongised- diphthongised

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can diphthongise
you can diphthongise
he can diphthongise
we can diphthongise
you can diphthongise
they can diphthongise 	I can be diphthongising
you can be diphthongising
he can be diphthongising
we can be diphthongising
you can be diphthongising
they can be diphthongising	I can have diphthongised
you can have diphthongised
he can have diphthongised
we can have diphthongised
you can have diphthongised
they can have diphthongised	I can have been diphthongising
you can have been diphthongising
he can have been diphthongising
we can have been diphthongising
you can have been diphthongising
they can have been diphthongising	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can't diphthongise
you can't diphthongise
he can't diphthongise
we can't diphthongise
you can't diphthongise
they can't diphthongise 	I can't be diphthongising
you can't be diphthongising
he can't be diphthongising
we can't be diphthongising
you can't be diphthongising
they can't be diphthongising	I can't have diphthongised
you can't have diphthongised
he can't have diphthongised
we can't have diphthongised
you can't have diphthongised
they can't have diphthongised	I can't have been diphthongising
you can't have been diphthongising
he can't have been diphthongising
we can't have been diphthongising
you can't have been diphthongising
they can't have been diphthongising	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I diphthongise?
can you diphthongise?
can he diphthongise?
can we diphthongise?
can you diphthongise?
can they diphthongise? 	can I be diphthongising?
can you be diphthongising?
can he be diphthongising?
can we be diphthongising?
can you be diphthongising?
can they be diphthongising? 	can I have diphthongised?
can you have diphthongised?
can he have diphthongised?
can we have diphthongised?
can you have diphthongised?
can they have diphthongised? 	can I have been diphthongising?
can you have been diphthongising?
can he have been diphthongising?
can we have been diphthongising?
can you have been diphthongising?
can they have been diphthongising? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can't I diphthongise?
can't you diphthongise?
can't he diphthongise?
can't we diphthongise?
can't you diphthongise?
can't they diphthongise? 	can't I be diphthongising?
can't you be diphthongising?
can't he be diphthongising?
can't we be diphthongising?
can't you be diphthongising?
can't they be diphthongising? 	can't I have diphthongised?
can't you have diphthongised?
can't he have diphthongised?
can't we have diphthongised?
can't you have diphthongised?
can't they have diphthongised? 	can't I have been diphthongising?
can't you have been diphthongising?
can't he have been diphthongising?
can't we have been diphthongising?
can't you have been diphthongising?
can't they have been diphthongising?