Question: In this sentence: 做乜唔叫埋我? What is the function of 埋?

I understood this sentence to be: "why didn't you call me?" (perhaps to an outing or a party). What is the difference with the sentence "做乜唔叫我"?

Insights please.

Answer: 
1. [V + **埋**] = [**也** + V] = [V + **too**]

Example:

* 叫**埋**佢去 = **也**叫他去 = ask him to go **too**
* 殺**埋**佢隻狗 = **也**殺了他的狗 = kill his dog **too**
* 連你都打**埋** = 連你**也一起**打 = beat even you **too**

2. [V + 埋] = [V + 完] = [finish + V]

Example:

* 執**埋**啲手尾 = 辦**完**那些收尾工作 = **finish** those finishing work
* 計**埋**條數就走 = 計算**完**那筆賬就走 = leave after **finish** calculating the account
* 食**埋**飯先至睇電視 = 吃**完**飯才看電視 = watch T.V. only after **finish** eating dinner

3. [V + 埋] = [V + result particle that means 'conceal'

Example:

* 收**埋**你把手槍 = 收**起**你的手槍 = put away (**and conceal**) your handgun
* 快啲匿**埋** = 快些躲**起來** = hurry up and hide (**and conceal yourself**)

4. [V + 埋] = [V + 貼/ 近] = [V + close]

Example:

* 企**埋啲** = 站**近些** = stand **closer**
* 閂**埋**門打仔 = 關**上**門打兒子 = close the door (**shut**) and beat the son

To answer your question:

> 
> 做乜唔叫**埋**我? = 為什麼不**也一起**叫我? (Why not call me **too**?)
> 
> 
> 

> 
> "做乜唔叫我"? = 為什麼不叫我? (Why not call me?)
> 
> 
>
As verbal suffix, 埋 can function as a verb complement with a lexical meaning somewhat like "close, tight". In this case, it can be used together with an adverb of degree (such as 好，太) and 咗. For example:

1. 唔好企太埋。(Don't stand too close.)
2. 佢关埋咗度门。（He has closed the door (tightly).)

In a sentence like 做乜唔叫埋我?, 埋 functions as an aspect marker. In this case, it cannot be used together with an adverb of degree (such as 好，太) and 咗. And like many other aspect markers in Cantonese (e.g. 住，到，紧，亲...), 埋 "has lost" its lexical meaning through abstraction and become an aspect marker. The interpretation of the process where 埋 is used is a function of it's underlying value and the context.

As an aspect marker, 埋 is used in contexts where we have a class of possible values constructed as fragmentable or dissociable. For example:

3. 唔准玩，做埋啲功课先。(You are not allowed to play. Finish your homework first.)
4. 今日下午我地踢波，叫埋阿民啦。(We are playing soccer this afternoon. Let Ah Min join us.)

In (3), "homework" is constructed as a "fragmentable amount of work". You have already started, but there is still a fragment that remains to be done. In (4), there are a group of people who can play soccer together. 阿民 is singled out in the beginning as the one who may or may not play together.

In these examples, 埋 serves to cancel the fragmentation and return the class as a whole.