Table 4 Description of ELFC-MLD category definitions, with illustrative quotes from caregivers

0: Communicates in complete sentences at a quality and performance normal for age

• This was relevant all the way up till the age of 2 years old and 7 months. I would say at 2 years old and 7 months is when we started noticing the decline so from before then, everything she could complete in full sentences, talk to you, didn’t know a stranger, talked to everybody (Interview 3)

• That would apply to her, yeah (Interview 5)

• Yes. Probably really from the time she started. Let’s say 2½ years, 2 years (Interview 1)

1: Communicates in complete sentences at a reduced quality and performance for age

• Yes, and that would probably be 26 to 28 months. So, for about 2 months, I’d say it was kind of declining (Interview 4)

• Yes and I’d say she did that, it’s hard to say when her sentences kind of weaned off and I’d say may be for few months maybe 1 month. 1 to 2 months (Interview 5)

2: Cannot communicate in complete sentences, but able to use 2-word phrases

• Yes but only for, really only for a couple months. Cause he kind of went … he went from saying more to just saying those one words (Interview 6)

• Yeah. I’d say that was probably around [date removed]. So, she would have been 27 months, 28 months (Interview 8)

3: Cannot communicate in 2-word phrases, but able to use single, meaningful words/ideas

• Maybe just like the yes/no kind of stuff. [Date removed] he was … a little bit after 4. And 4 was, yeah, I would say like [date removed], around there (Interview 7)

• Sorry, I’m flashing back in my memory. Yeah, I think he did. Like I think … I think he did for a very short time (Interview 4)

4: Complete loss of expressive language

• So, complete loss of expressive language, which … that happened so rapidly. She’s been like that for years (Interview 11)

• And then she’s been ‘complete loss of expressive language’, gosh for probably 5 years now (Interview 1)