This paper aims at analyzing the multifunctionality of the adverbs aí and assim in Brazilian Portuguese (BP; Iboruna Corpus) within Functional Discourse Grammar – FDG – (Hengeveld & Mackenzie, 2006, 2008) and Grammaticalization Theory (GR; Hopper & Traugott, 1993), regarding their interpersonal and representational roles in the language.In BP many adverbs of time, place and manner can function as anaphoric and cataphoric elements, conjunctions, conversational signals, focus markers and discourse markers. Examples of aí and assim in their basic lexical uses are given in (1) and (2): 

(1)  eu tenho uma colega...e a casa dela fica aí
       'I have a friend and her house is there’ 

(2) ele viveu a vida assim [desse modo]...
       'He lived the life like that ‘

Examples that support the GR hypothesis of these adverbs are given in (3-5): 

(3) João foi comprar comida no restaurante, assim todos poderão almoçar aqui. 
      "John went to buy food in the restaurant, therefore all will have lunch here.’

In (3) the manner adverb assim functions as a conjunctional element that in terms of FDG expresses a concluding semantic relation between the two episodes João foi comprar comida no restaurante and todos poderão almoçar aqui, which hierarchically constitute a propositional content at the Representational Level. In (3), besides the temporal markers of the units (past in the first and future in the second), both episodes are located independently in time and space (Hengeveld & Mackenzie, 2008). In addition, a propositional modifier like probably can be allocated at the beginning of the sentence to scope both episodes at the same time as a single proposition. The adverb aí may also occur as a conjunction, as in (4): 

(4) (Sinceramente/ *Certamente) Tem que surpreender o adversário. Aí eu acredito na vitória.
     ‘(Sincerely/*Certainly) S/he has to surprise the opponent. Thus, I believe in the success.'
      RL: (p₁) (l_i: (f_i: aí_conj (f_i)) (l_i)) (p₂)  

(5) Tome cuidado assim vc poderá um dia tbém se machucar.
      'Watch out, thus/because you will hurt yourself one day.’ 
  IL: [( ПA₁: [tome cuidado] (A₁)) (П A₂: [vc poderá um dia tbém se machucar] (A₂))_Motiv] (M₁))Φ

In (4) aí is functioning as a conjunction that establishes a concluding relation between two propositional contents, and the modifier sinceramente attests this. In (5), assim is used as a conjunctional element to introduce a comment about the discourse act expressed in the main clause, and thus functioning at the interpersonal level (cf. Hengeveld & Wanders, 2007).

With these examples, I have tried to show that there is (or it seems to exist) a GR process that starts at the Representational level and ends with aí and assim functioning as conjunctions at the Interpersonal level. Longhin-Thomazi (2006), for instance, shows that in earlier stages of Portuguese assim (assi) was limited to uses at the Representational level.