International legal cases, from maritime arbitrations to prosecutions for breach of patent, may need interpreters.

Lucia Alvarez de Toledo and Franoise Delas-Reisz offer some guidance on the problems this poses

Lawyers often find themselves co-ordinating large teams.

One recent international fraud case ran for three weeks and involved three different groups of witnesses - Italian insurers, Danish merchants and Argentine river pilots - and they were matched with parallel sets of interpreters.

Such situations are understandably stressful for lawyers.

Interpreters seem only to interrupt a lawyer's flow and prolong the proceedings, and it is natural to feel anxious about loss of control.

Nonetheless, interpreters are there to help and, by taking care of the language issues, can allow lawyers to focus on winning the case.

Instead of creating a barrier, as is sometimes feared, interpreters can streamline communications and increase a lawyer's efficiency.

Creating a team

Interpreters can vary widely in quality - and lawyers can never be sure in advance what they are going to get.

First-hand experience is the only totally reliable guide, so it is often a good idea to ask colleagues or other contacts for a recommendation.

(If you've ever employed interpreters who were so unobtrusive you forgot they were there - which is the self-effacing ideal - remember to keep their details on file.)

It is often a mistake to be guided solely by cost.

As skilled professionals, interpreters are not cheap, but they represent a tiny proportion of the budget for a major international case.

Yet even an interpreter who just happens to be a bit slow can cause significant delays and greatly hamper the process of cross-examination.

It seldom makes sense to go for second-best.

Therefore, while it is often quicker and more convenient to access interpreters through an agency, remember that agencies may conduct Dutch auctions to keep their prices down.

In any event, it is usually well worth meeting with potential interpreters and asking to see CVs and testimonials from other lawyers.

Lawyers can legitimately expect interpreters who specialise in legal work to have a good general grasp of British law, their own national law and the differences between the two (although they are obviously unlikely to be experts in particular fields such as fishing quotas or intellectual property rights).

Always employ experienced professionals.

Speaking a foreign language fluently or being brought up bilingual doesn't make someone an interpreter.

Many excellent translators of legal documents are ineffective interpreters, so don't rely on the people who translate contracts for you.

Few interpreters can work effectively for more than 45 minutes without a break, so it is often necessary to employ a team of two or more.

In a complex case, it is far more effective to use the same interpreter(s) throughout.

Where a change midstream is unavoidable, try to ensure that the outgoing interpreters brief the replacements as to the basic facts and key legal issues at stake.

It is not permitted in court, but for arbitrations and other more informal proceedings it is often worth exploring the option of simultaneous interpretation.

As the lawyer asks a question, the interpreter puts it to the witness in the witness's own language through a headset; the lawyer (and everybody else taking part) will then hear the answer in English through an earpiece.

This saves time and doesn't interfere with the cut and thrust of cross-examination.

Most interpreters and agencies can provide guidance on where to hire the relevant sound equipment.

Lawyers keen to make the interpreting process even less disruptive should look into the option of setting up temporary booths for interpreters (where space allows).

Never make assumptions about the language a witness will speak on the basis of your own experience of a country.

Even a citizen of Belgium, Italy, Spain or Switzerland, never mind India or Indonesia, may be a native speaker of several different languages or regional dialects, so always ensure you know in advance and employ an interpreter with the right background.

Always supply interpreters with translated documents in both languages in advance.

Either version may be quoted verbatim in court.

This will save the court's time and make it far easier for witnesses to understand the points at issue.

Always treat your interpreters as part of the team and try to brief them as fully as possible.

They can often provide valuable pointers on cultural issues such as forms of address and whether it is considered polite to look people in the eye.

It is usually helpful for the witness(es) and interpreter(s) to meet beforehand to iron out any problems and to reassure the witness(es) that they will be able to get their exact meaning across in another language.

In court

Even when they form part of your team, remember that interpreters are under oath and bound by a code of ethics to show no bias and to convey the meaning as accurately as possible (even when a witness is rude, offensive or in other respects unhelpful to your case).

However, they will often 'tidy up' a particularly rambling or incoherent speaker to avoid wasting the court's time.

Be careful about using heavy irony or linguistic tricks like double negatives to catch out a foreign witness.

Such devices often fall flat when interpreted at speed, so consult your interpreter in advance about whether they will work or warn them of what you are planning.

Don't forget that words that sound similar and have the same origin may mean different things in different languages.

This applies both to technical and everyday vocabulary.

An English notary performs different tasks from a French notaire.

'To ask' in French is demander, while 'to demand' is exiger.

You can assume that a professional interpreter will get such things right, so (even if you are fluent in the language) don't feel the need to intervene.

Interpreters are there to serve the court and will usually be willing to provide stenographers with the spelling of difficult proper names or place names.

During tense multilingual negotiations or legal disputes, it is not unusual for people to blame the interpreters when things get sticky.

Interpreters tend not to take too kindly to such slurs on their professionalism.

If you must fall back on this ploy in the heat of battle, remember to apologise afterwards.

Lucia Alvarez de Toledo and Franoise Delas-Reisz work as interpreters and translators in French, Spanish and Italian