Impact of enriched meaning representations for language generation in dialogue tasks: A comprehensive exploration of the relevance of tasks, corpora and metrics
Organizations: Speech Interactive Group, University of the Basque Country (UPV/EHU), Sarriena s/n, 48940 Leioa, Spain
Abstract
Conversational systems should generate diverse language forms to interact fluently and accurately with users. In this context, Natural Language Generation (NLG) engines convert Meaning Representations (MRs) into sentences, directly influencing user perception. These MRs usually encode the communicative function (e.g., inform, request, confirm) via DAs and enumerate the semantic content with slot-value pairs. In this work, our objective is to analyse whether providing a task demonstrator to the generator enhances the generations of a fine-tuned model. This demonstrator is an MR-sentence pair extracted from the original dataset that enriches the input at training and inference time. The analysis involves five metrics that focus on different linguistic aspects, and four datasets that differ in multiple features, such as domain, size, lexicon, MR variability, and acquisition process. To the best of our knowledge, this is the first study on dialogue NLG implementing a comparative analysis of the impact of MRs on generation quality across domains, corpus characteristics, and the metrics used to evaluate these generations. Our key insight is that the proposed enriched inputs are effective for complex tasks and small datasets with high variability in MRs and sentences. They are also beneficial in zero-shot settings for any domain. Moreover, the analysis of the metrics shows that semantic metrics capture generation quality more accurately than lexical metrics. In addition, among these semantic metrics, those trained with human ratings can detect omissions and other subtle semantic issues that embedding-based metrics often miss. Finally, the evolution of the metric scores and the excellent results for Slot Accuracy and Dialogue Act Accuracy demonstrate that the generative models present fast adaptability to different tasks and robustness at semantic and communicative intention levels.
Figures & tables
| MR | Sentence |
|---|---|
| inform (name = The Vaults ; eatType = pub ; priceRange = more than £30 ; customerRating = 5 out of 5 ; near = Café Adriatic) | The Vaults pub near Café Adriatic has a 5 star rating. Prices start at £30. |
| inform ( name = The Cambridge Blue ; eatType = pub ; food = English ; priceRange = cheap ; near = Café Brazil ) | Close to Café Brazil, The Cambridge Blue pub serves delicious Tuscan Beef for the cheap price of £10.50. Delicious Pub food. |
| MR | Sentence |
|---|---|
| inform ( name = The Forest of Doom ; release_year = 2014 ; genres = role-playing, text adventure ; has_multiplayer = no ) | The Forest of Doom is a role-playing text adventure game released in 2014. It is a single-player only game. |
| give_opinion ( name = Undertale ; esrb = E (for Everyone) ; rating = excellent ) | Undertale is a downright excellent game, and it’s rated E so everyone can enjoy it. |
| request_attribute ( has_multiplayer = ? ) | Do you prefer to game with others, I mean, multiplayer? |
| MR | Sentence |
|---|---|
| SYSTEM_Booking_Book ( bookday = Wednesday ; bookpeople = five ; booktime = 11 am ; name = this restaurant ; ref = DU8IWQZ2 ) & SYSTEM_Restaurant_Inform ( address = 2 Rose Crescent City Centre ; name = The Gardenia ) | The Gardenia is located at 2 Rose Crescent City Centre. I have booked your table at this restaurant for five people, Wednesday at 11 am. Your reference number is DU8IWQZ2. |
| USER_general_thank ( ) | No that will be all, thank you. |
| MR | Sentence |
|---|---|
| Gen_Hello ( user_name = Elisabeth ) | Hello Elisabeth! |
| Int_know_coaching ( ) | Do you know what coaching is? |
| GSQ_what_obj ( action = change ) | Would you like to change anything? |
| RQ_curr_sit ( food = water ) | Do you think you’re drinking enough water? |
| Dataset | Domains | Acquisition process | Number of DAs | Number of attributes | Number of MRs | Corpus size | Running words | Vocabulary |
|---|---|---|---|---|---|---|---|---|
| E2E | Restaurants | Crowd | 1 | 8 | 6.0k | 51k | 1.0M | 5.1k |
| ViGGO | Video games | Crowd | 9 | 14 | 2.3k | 6.9k | 150k | 4.4k |
| MultiWOZ | 7 domains | WOZ + Crowd | 798 (52) | 25 | 54k | 140k | 1.9M | 30k |
| EMPATHIC | Coaching | WOZ | 78 | 21 | 1.2k | 2.3k | 13k | 1.7k |
| Dataset | Example type | Examples |
| E2E | Input MR | inform ( name = Zizzi ; eatType = coffee shop ; customer rating = high ; near = Burger King ) |
| Prompt 2 demonstrator | inform ( name = Loch Fyne ; eatType = restaurant ; familyFriendly = yes ; food = English ) + A child friendly restaurant that has English food is Loch Fyne. | |
| Prompt 3 demonstrator | inform ( name = Wildwood ; near = Café Rouge ; customer rating = low ; eatType = restaurant ) + Wildwood, a restaurant with a low customer rating, is near Café Rouge. | |
| ViGOO | Input MR | give_opinion ( name = Super Mario World ; player_perspective = side view ; rating = excellent ; has_multiplayer = yes ) |
| Prompt 1 demonstrator | give_opinion ( name = Guitar Hero: Smash Hits ; rating = poor ; developer = Beenox ) + Guitar Hero: Smash Hits is just not my kind of game. I find Beenox games are often not very fun. | |
| Prompt 2 demonstrator | give_opinion ( name = Worms: Reloaded ; player_perspective = side view ; rating = average ; available_on_Steam = yes ) + Worms: Reloaded is an average quality side view game you can at least find on Steam. |
| Dataset | Prompt 1 | Prompt 2 | Prompt 3 |
|---|---|---|---|
| E2E | - 7 7 7 There is no Prompt 1 representation for E2E, because E2E only has one DA, so all the MRs from the original corpus would be connected to the same demonstrator for this representation. | 6 | 120 |
| ViGOO | 9 | 21 | 473 |
| MultiWOZ | 798 | 2281 | 11644 |
| EMPATHIC | 78 | 197 | 537 |
| Data | Base | P1 | P2 | P3 |
|---|---|---|---|---|
| E2E | 0.79 | - | 0.65 | 0.67 |
| ViG | 0.80 | 0.69 | 0.72 | 0.72 |
| MWOZ | 0.94 | 0.91 | 0.91 | 0.91 |
| EMP | 0.88 | 0.86 | 0.87 | 0.90 |
| Data | Val | Base | P1 | P2 | P3 |
|---|---|---|---|---|---|
| ViG | 0.98 | 0.99 | 0.65 | 0.89 | 0.94 |
| MWOZ | 0.85 | 0.86 | 0.52 | 0.68 | 0.83 |
| EMP | 0.68 | 0.65 | 0.72 | 0.70 | 0.70 |
| MR | inform ( name = Crysis ; release_year = 2007 ; esrb = M (for Mature) ; rating = good ; genres = action-adventure, shooter ; has_multiplayer = yes ) | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| References | 3 references: - A solid M-rated action-adventure shooter, Crysis, came out in 2007. The game offers multiplayer. - An action-adventure shooter game for mature audiences is the 2007 game, Crysis. It was a fun game offering also a multiplayer mode. - Crysis is an action-adventure shooter that was released in 2007, rated M (for Mature). It is considered good quality, and has multiplayer mode. | ||||||||
| Generation | Crysis is an action-adventure shooter released in 2007. It has received good reviews. | ||||||||
| Dataset | ViGOO | BLEU | 0.06 | BLEURT | 0.66 | LaBSE | 0.81 | Slot acc | 0.80 |
| MR | Gen_Open_question ( action = cook ; food = fish ) | ||||||||
| References | 1 reference: What’s your favourite fish to cook? | ||||||||
| Generation | Do you like to cook fish? | ||||||||
| MR | inform ( name = Tony Hawk’s Pro Skater 3 ; release_year = 2001 ; esrb = T (for Teen) ; genres = sport ; player_perspective = third person ) | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| References | 3 references: - Tony Hawk’s Pro Skater 3 was released in 2001. It is a third person sports game that is rated T (for Teen). - Tony Hawk’s Pro Skater 3 was a third person sport game released in 2001. It was rated T (for Teen). - Another third person perspective sport game is Tony Hawk’s Pro Skater 3. It came out in 2001 and is rated T (for Teen). | ||||||||
| Generation | The 2001 sport game, Tony Hawk’s Pro Skater 3, was a third person game. It has a t (for teen) rating and is rated t (for physical). | ||||||||
| Dataset | ViGGO | BLEU | 0.34 | BLEURT | 0.61 | LaBSE | 0.92 | Slot acc | 1.00 |
| MR | Gen_Agreement ( ) | ||||||||
| References | 91 references: - Absolutely - Of course. - Yeah - Right - I totally understand. - (86 references more) | ||||||||
| Generation | Sure. | ||||||||
| MR | inform ( name = HSS ; genres = adventure, hack-and-slash, indie ; platforms = PlayStation, Xbox, PC ; available_on_steam = yes ; has_linux_release = no ; has_mac_release = no ) | ||||||||
| References | 3 references: - HSS is an indie adventure, hack-and-slash game for PlayStation, Xbox, and PC. It is available for Steam, however, it is not out for Linux or even Mac. - HSS is an indie hack-and-slash adventure game available on Steam. You can play it on PlayStation, Xbox, and PC, but not on Linux or Mac. - HSS is an indie, adventure, hack-and-slash game that’s available on PlayStation, Xbox and PC. You can also get it from Steam, but it does not have Linux or Mac releases. | ||||||||
| Prompt 3 task demonstrator | inform ( name = The Sims ; genres = simulation, strategy ; platforms = PlayStation, Xbox, Nintendo, PC ; available_on_steam = no ; has_linux_release = no ; has_mac_release = yes ) + The Sims is a simulation-strategy game that is available for PlayStation, Xbox, Nintendo, and PC. It can operate on Mac, but it is not released for Linux. It is not available on Steam. | ||||||||
| Baseline Generations | 15 generations: - HSS is an indie adventure hack-and-slash game. It’s available on the following platforms: PlayStation, Xbox, and PC. Steam is also the home of the game, though it isn’t available for Linux or Mac. - If you’re into indie adventure and hack-and-slash games, try HSS. It’s an indie game released for PlayStation, Xbox, PC, and Mac. You can get it on Steam now. - If you like indie hack-and-slash adventures on the PC, try HSS. It’s available on Steam, and you can play it on all platforms, such as the PlayStation, Xbox, and PC. There was no Linux or Mac release. - (12 generations more) | ||||||||
| Prompt 3 Generations | 15 generations: - HSS is an indie adventure-shooter with puzzle solving elements. - HSS is an indie adventure-hack and slash with a Mac twist. - HSS is an indie adventure-hack-and-slash on the PC that has been released on Steam. - (12 generations more) | ||||||||
| Dataset | ViGGO | BLEU | 0.31 / 0.15 | BLEURT | 0.70 / 0.56 | LaBSE | 0.89 / 0.68 | Slot acc | 0.82 / 0.33 |
| MR | Gen_Open_topic ( hobbies = travel ) | ||||||||
Text Generation
Text generation studies methods for producing coherent, useful language from prompts, data, and dialogue context.
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