Dear Russian Language Mentor,

I often encounter the particle -ка in spoken Russian. For example, suffixed to the familiar/singular imperative: Иди-ка сюда! Позвони-ка домой! Or simply in expressions like Ну-ка.
What is the function of this particle and how does it translate into English?
No кака jokes, please!

Gentle Linguist,

Okay, no кака jokes!

So this mushroom walks into a bar during "Happy Hour," and the barkeep yells, "Hey, what are you doing in here? Get out! You don't belong here!" And so the mushroom says, "What do you mean? I'm a fungi!"

Now on to your question:

Let's take the imperatives first. The "polite" form of the imperative is, of course, the plural "вы" form. But aspect also plays a role in "polite imperative" commands. In this sense, the imperfective imperative is considered "more polite" than the perfective. Thus "Садитесь!" is what you'd expect a hostess to say when asking her guests to sit down at the table, not "Садьте!"

While the perfective imperative is not as polite as the imperfective, its force can be modified or "softened" with a пожалуйста or with the colloquial particle -ка, which adds a sense of familiarity or friendliness to a command:

• Помолчи-ка. "Quiet down."
  
• Скажи-ка мне. "Do tell me."
  
• Запиши-ка мой телефон. "Why don't you write down my number."
  
• Дай-ка мне посмотреть. "Do let me see."
  
• А ну, малы, подай-ка мне эту штуку! "Hey, little guy, hand that thing over to me."

Mind you, the -ка particle can also be added to the plural imperative:

• Нет, так не пойдет, давайте-ка сначала.
  "No, this won't work. Why don't we start from the beginning."
  
• Пойдите-ка включите первую программу.
  "Would you mind going up and putting on channel 1."
  
• Отсыпьте-ка мне на тыщу рублей стакан семечек.
  "Could you pour me a thousand-ruble tumbler of sunflower seeds?" (Talk about inflation!)

The colloquial ну-ка also tends to be used in an imperative context as something of a "polite encouraging" phrase:

• Ну-ка, быстренко ксерокопию мне.
  "Could you hurry that xeroxed-copy to me?"
  
• Ну-ка, покажи нам твою комнату.
  "Come on, show us your room."
  
• Ну-ка поставь пластинку и раздевайся.
  "Well now, why don't you put on a record and take off your clothes."
  (This last example was taken from Izvestiya!)

Finally, the particle -ка is also encountered with the 1st person singular of the future tense perfective to express a decision or an intention to do something, similar to the English phrase, "I think I'll...":

• Напишу-ка ему письмо.
  "I think I'll write him a letter."
  
• Пойду-ка домой.
  "I think I'll go home."
  
• Схожу-ка я опять за кока-колой. "I think I'll go get another coke."

In a similar sense, the particle -ка can be added to дай and давай in 1st person singular expressions:

• Дай-ка согрею ладони.
  "I think I'll warm up my hands."
  
• Давай-ка зайду к соседу.
  "I think I'll drop in on my neighbor."

Confusing the issue a tad, the particle -ка is also encountered in interrogative contexts with the 1st person singular of the perfective future when the speaker intends to do something and invites comment - the "what if I..." in English :

• Куплю-ка я эту книгу.
  "What if I buy this book?"
  
• А попрошу-ка я у него помощи.
  "So what if I ask him for some help?"

What helps distinguish the interrogative "what if I" from the declarative "I think I'll" in the spoken language is intonation. In the written language, you need to examine the context very carefully.

Well now, you have a good day. What if I munch on some of those sunflower seeds and mushrooms and then take a nap? I think I'll do that...

Peace to you,

The RLM

("Crunch, crunch..." ZZZZZZZzzzzzzzzzzzzz.........)