Tonicity is a system whose main tenet is expressed by the Last Lexical Item rule. The rule establishes that, unless there is a reason for doing otherwise, the nucleus of the IP –that is, its main accent- falls on the last lexical item. At this point two clarifications are needed. First the distinction between lexical words (nouns, adjectives, adverbs and most verbs), which are those words which convey a clear meaning, and function words (prepositions, articles, conjunctions, pronouns auxiliary verbs, modal verbs and the copula verb be), which are best described in terms of their syntactic function. Second, it must be taken into account the fact that the rule talks about “lexical items” and not words in order to include compounds.

Let’s see an example of how the LLI rule works:

In the utterance

(1) I don’t know what she’s talking about.

the nucleus falls on the verb talking and not on the preposition about. In general this is somewhat difficult to grasp for Spanish speakers because the default word for the nucleus in Spanish is always the last one. But unfortunately there is a world of difference in terms of pronunciation between saying

(2) I don’t know what she’s talking about.

 

and

(3) *I don’t know what she’s talking about.

 

(2) is the correct, unmarked version in English and, if we produce (3), we are placing an unnatural emphasis on a preposition, which might puzzle our interlocutor and make him or her wonder if we are trying to imply something different. In the end, this will result in an unmistakingly foreign accent.
The matter becomes more complicated because we can have several function words in a row at the end of an IP, which will make the decision about the nucleus less straightforward. In this case, we will have to go back in search of the last lexical item. For example:

(4) We know he’s been stealing money, but we’ve never caught him at it.

 

If we proceed backwards along the sentence, we will find:

1. The neutral pronoun it –a function word-.
2. The preposition at –another function word-.
3. The personal masculine pronoun him –a function word again-.
4. The verb caught, which is a lexical word and consequently receives the main accent.

Let’s now have a look at a couple of examples taken from real life.

(5) Before I do that, there’s something I want to talk to you about (Frank Alberston; Fergus Falls, Minnesota, US)
(6) His novel, Be near me, is a beautiful and poignant exploration of a life of a catholic priest, father David, who does not, it’s fair to say, have a very good time of it (James Naughtie; Aberdeenshire, Scotland).