In case I have missed anything, obvious or otherwise;

have made notes so far- these include,

• discussing with parents what has happened in child's life up until this point,
• eg family upbringing- does child have a sibling who may be "talking" for them, like walking, talking late could be a family trait
• medical issues- eg premature babies may lag slightly behind full-term peers,
• is child bilingual as this could cause a delay,
• are there lots of opportunities for communication with parents & other adults- doesz child see a "need" to communicate
• appointment with Dr/medical- hearing test, Speech & Language Therapists,

Many thanks in advance for your replies