In what language should I address foreign customs and immigration?

The answer to the general question is: It depends. The general options are as follows:

1. I always address U.S. and U.K. border guards in their language, because I don't expect them to understand any other I can speak nearly as fluently.
2. I will always try to address French border police in their language, although I can't really speak it, because they are proud of anyone at least trying, but I will make sure that they know that I am not fluent.
3. I would never address Dutch or Swedish police in Dutch or Swedish, even though I possibly could. They can speak English, and I want them to know that I am a foreigner who intends to move back to his country. Some days ago we had a Russian guy who was nearly deported for just greeting a Finnish border guard in Finnish ("You learned Finnish because you intend to blend in and stay over your visa").

With special regard to Central America, if I were you, I would take option 2 and greet a border guard there with "Buenos dias, señor. ¿Habla inglés?"

Your best bet is to not speak at all. If they ask you to do anything (take your hat off, look into the camera), just do it without a word.

Once you get everything stamped and taken care, they will usually say something, and usually in English. At that point, it would be polite to thank them in their native language.

As a European living in a part of South Asia where I speak the language:

I speak to the natives here in their own language pretty much always. One of the very few exceptions to this is when I go through immigration at the airport here. Why? Because that's the one place where I don't want to get stuck! I just want to go through quickly! Why would I want to complicate things? I have a visa, they're just gonna stamp it and let me through. Speaking the local language probably wouldn't cause a problem, but why would I risk it? They may start to ask me all kinds of questions (if out of curiosity, if nothing else.) Where did I learn it? How? When? What am I doing here? How many times have I been here? (Even civilians ask me that, out of curiosity.) While I have perfectly fine answers to all that, I just don't want to have that conversation with the immigration officer, I just want to go through. So if asked anything, I answer in English.

If, in a very unlikely scenario, the officer didn't speak English and there was a serious communication problem, I would probably switch. But that seems like it's only going to happen like 0.01% of the time.

I'd advise you to stick to English, leaving the Spanish for after you've gone through immigration.

The entire purpose of forcing people to interact with custom agents is so the custom agent can intuitive evaluate the individual as some kind of potential threat.

Nobody ends up in the backroom with the one-way mirror because they blurt out some crime or have a carry-on stuff with cocaine, bioweapons and 1960s vintage Warsaw-pact plastic explosives. They end up in the backroom because they set off the custom agent's intuition.

They don't care whether you answer "business" or "pleasure" they care how you answer e.g. shifts in verbal tone or, general body language, leaning away or toward the agent as you answer, breaking eye contact, turning to talk to a companion before answering the agent etc. That's why they ask seemingly inane questions and/or make you dump out a suitcase that's already been X-rayed 16 times that day. They just want to put you under an lens, poke at you a bit and see how you jump.

As a general rule, its safest to avoid attention and limit interaction time with custom agents since you don't know what might you might do or say that will trigger their intuition or their venality. The less information they can intuitively pull out of you the better.

In the 3rd world, the biggest risk is being falsely accused as part of shakedown because the custom agents haven't been paid for six months. In the 3rd world everything runs on personal connections so a corrupt agent will be looking for someone with money but no protective connections.

I know a lot of people who traveled for decades in the oil industry and, since they had wear expensive business suits and looked well off, they could be targeted so they learned to always mention the name of the company they work for and that they would soon be meeting other company employees. If possible, mentioning the name of local grandee was also a good idea. You didn't want to convey the impression that you were someone who could drop off the map for days or weeks and no one would notice.

In your particular case, assuming your not actually breaking a law or can't handle speaking with authorities, I doubt it matters what language you speak.

Costa Rica airports are safe and well run for the third world partially because Costa Rica disbanded its army after WWII and the US assures its territorial integrity which these days means transportation security as well. Besides, Costa Rican's are just generally nice, kinda the Canadians of Central America.

Panama I'm pretty sure is still an American protectorate, at least for areas related to the canal. I assume the airports and other entry points are under American supervision.

I travel to asia often (China, Japan, Korea, Taiwan, Hong Kong), and in all cases, they assume you can't speak their language if you look non-asian. So if you do speak their language, it generally catches them off-guard and they may ask you more questions.

Only issue I ever had, was in Japan of all places. They asked me why I traveled there so often and asked me in Japanese if I spoke Japanese (which I could understand barely), but I responded in english (I'm from US). They thought I might be transporting drugs into/out of Japan. As a business traveler I flew in/out of Japan quite often and often had short trips there for my company. So after answering a few questions and telling them what company I was visiting and what company I work for, they sent me on my way.

So generally they profile people and ask pointed questions directed towards those kinds of people. Basically like if you are from such and such countries they would assume they are coming there to buy lots of foreign goods -- which are not allowed to be greater than a certain value -- so they ask about that.

Basically they have a long list either in their head or on paper that probably says stuff like, "Koreans ask about blah, Filipinos ask about blah, main land chinese ask about blah, japanese ask about blah, etc...".. So in their case, I would also advise like others, just stick to english and keep your answers really really short and succinct.

Going through immigration or customs is a completely subjective process:

It depends on where you are, where you are from, where you're coming from, where you're going, who you are with, what you're wearing, who the customer officer is, and if he had a bad day...

Therefore I would recommend to stick to:

• Greetings: be polite, and say hello. Unless you're in transit, I would hope you spent the 3 minutes it takes to learn to say 'Hello' in the country you're visiting.

• Questions: let the officer speak first: s/he will never expect you to be fluent, but if his/her English is poor you might be asked in the local language. Try to answer in the language and get in the officer's good grace. If you're not sure you understood the question, or don't feel confident about answering in the local language, politely ask 'Do you speak English?' or rather say something like 'My spanish/chinese/croatian is not very good, do you speak English?'

• If you're in trouble and the language is an issue they'll likely fetch someone who speaks better English; In my experience, if there is nothing major and the language is an issue, they usually give up asking questions and tell you to move on...

Finally I would add: be mindful of the local culture. Do your research to avoid making a derogatory comment and offend anyone.

I am Swedish but live in Switzerland and speak fluent German. When showing my ID Card to border guards at Zurich Airport, they often ask me in English where I'm flying from/to, and in rare cases how long I'll stay in Switzerland. I then simply answer in German, without making a fuss about it.

I'd say if the border guards seem to speak English better than you speak the local tongue, stick to English. However, I've had several occasions (mainly in the former Yugoslavia and Albania, but also Turkey) where the border guards didn't know a word of English (or any foreign language), and the fact that I didn't understand the questions they were asking (the times that they did) severely delayed my entry/Exit.

Moldovan border guards do not normally speak any English either (particularly at land borders), but as I speak Romanian pretty well it's not an issue there

I'm soon going to Russia, Kazakhstan, Azerbaijan and Georgia - going to be pretty interesting :)

Stick to English, Unless the officer does not understand English at all in which case you should talk in Spanish but lead with "mi español no es avanzado, pero que podría tratar de explicar".

I would say, it depends. If the passport you present is stamped with many stamps of a spanish-speaking country, or if you're carrying a spanish-written newspaper/book under your arm, I would tell you to speak spanish.

That being said, be aware that speaking spanish could put you in an entirely different category.

If you speak spanish fluently, then it may be that you're an expat wishing to live in the country, or have family in that country, and so you'd start getting questions about your laptop and any expensive electronics you're carrying. Because for all they know, you could be bringing that DSLR in and that laptop in as gifts for local friends or family (that you don't want to pay VAT or import taxes on), or perhaps, your language skill level could be an indicator that you may wish to overstay your visa.

In general, custom and border officials are not your friends. It wouldn't hurt to say a couple of words to them in spanish, but trying to make them feel at ease or impress them with your level of spanish would seem to me counter-productive, if your objective is to go through customs as smoothly as possible.