The Nijmegen Corpus of Casual Spanish

Francisco Torreira, Mirjam Ernestus

Radboud Universiteit Nijmegen & Max Planck Institute for PsycholinguisticsFrancisco.Torreira@mpi.nl, Mirjam.Ernestus@mpi.nl

AbstractThis article describes the preparation, recording and orthographic transcription of a new speech corpus, the Nijmegen Corpus of CasualSpanish (NCCSp). The corpus contains around 30 hours of recordings of 52 Madrid Spanish speakers engaged in conversations withfriends. The orthographic transcription contains around 393 000 word tokens and 16 500 word types. Casual speech was elicitedfollowing a procedure similar to that used for the creation of the Nijmegen Corpus of Casual French (Torreira et al., 2010). Therecordings consisted of three different parts, which together provided around ninety minutes of speech from every group of speakers.While Parts 1 and 2 did not require participants to perform any specific task, in Part 3 participants negotiated a common answer togeneral questions about society. The resulting corpus is a rich resource of highly casual speech that can be effectively exploited byresearchers in language science and technology. Information about how to obtain a copy of the corpus can be found online at http://mirjamernestus.ruhosting.nl/Ernestus/NCCSp

1. IntroductionSpanish is one of the best documented languagesin the world. However, to our knowledge no largecorpus of casual Spanish suitable for detailed pho-netic analysis is available. The goal of this arti-cle is to introduce the Nijmegen Corpus of CasualSpanish (NCCSp from now on), a new corpus de-signed to fill this gap. The corpus was designedtaking the Nijmegen Corpus of Casual French as amodel (Torreira et al., 2010), which was also col-lected in our lab. The uniqueness of the NCCSpcan be characterized as follows:

• It contains around 30 hours of casual conver-sations among groups of friends. This makesit possible to study a wide range of phenom-ena characteristic of casual speech.

• It contains speech from 52 native MadridSpanish speakers sharing a similar educa-tional background and age.

• It contains large amounts of data for ev-ery speaker (around 90 minutes of recordedspeech for every group of three speakers).This allows researchers to study within-speaker variability.

• It is orthographically transcribed.

• It contains audio as well as video data, whichcan be used for the study of facial and bodygestures during verbal communication.

The following sections provide a detailed de-scription of the creation and transcription of theNCCSp.

2. Corpus creation2.1. ParticipantsThe corpus creation was begun in March 2008. Agroup of university students were hired as confed-erates. These confederates were instructed abouttheir role and asked to find two friends willing toparticipate in recordings of natural conversations.These friends are referred to as speakers from nowon. Every recording consisted of a conversationamong these three participants: a confederate andtwo speakers. All participants complied with thefollowing conditions:

• They knew the two other participants in therecording well.

• They were of the same sex as the two otherparticipants in the recording.

• They were university students in Madrid.

• They had been raised in the Madrid region.

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Figure 1: Layout of the recording room.

• They reported not suffering from any pathol-ogy related to speech or hearing.

The corpus consists of 20 recordings (10 groups ofmale participants and 10 groups of female partic-ipants). Speakers were invited to act as confed-erates in later recordings. For this reason, nineparticipants took part in more than one recordingsession (first as a speaker and later as a confeder-ate). In total there were 52 participants (27 femaleand 25 male). All participants were university stu-dents aged between 19 and 25. More details aboutthe participants’ background will be available inthe NCCSp corpus package.

2.2. Recording set-upThe recordings took place in a sound-attenuatedbooth at the Universidad Politecnica de Madrid.The booth had an approximate size of 4 x 2 m.The participants sat on chairs around a table. Theconfederate always sat on the south side of the ta-ble, while the speakers occupied the chairs on thenorth and west sides. Figure 1 shows the layout ofthe recording room.The speakers were recorded on a Edirol R-09solid-state stereo recorder. Each speaker wasrecorded in a separate channel. The confederatewas directly recorded on a computer via a dedi-cated sound card. All participants wore a Sam-son QV head-mounted unidirectional microphone.The microphones were placed at an average dis-tance of 5 cm from the left corner of the speakers’lips. The sampling rate used was 44.1 KHz, andquantization was set to 32 bits.

Figure 2: Snapshot extracted from one of the filmsin the corpus.

The conversations were filmed using a Sony HDR-SR7 video camera. The camera was placed in acorner of the recording room in a position thatallowed us to film the two speakers, but not theconfederate. Figure 2 provides a sample snapshotfrom one of the films. In order to avoid inhibit-ing the speakers, we tried to make them believethat the camera was turned off during the record-ings. As a first step, a small piece of duck tapewas placed on each of its lights. Additionally, anunplugged cable was left hanging from the cam-era in order to reinforce the impression that it wasturned off. Moreover, the camera was not placedon a tripod also present in the room. Finally, weplaced several unused objects near the camera, in-cluding old boxes and cables, a computer screen,several loudspeakers and other audio equipment.As shown in Figure 3, our camera appeared asone among the numerous shut down devices in therecording room.

2.3. Recording procedureThe recording procedure was similar to that em-ployed during the collection of the Nijmegen Cor-pus of Casual French and the Nijmegen Corpus ofCasual Czech (http://mirjamernestus.ruhosting.nl/Ernestus/). Previous re-search has shown that this procedure is successfulat eliciting casual spontaneous speech (Torreira etal., 2010). This subsection describes the recordingsession in more detail.Preparations: Confederates arrived at the Univer-sidad Politecnica de Madrid for an interview withthe first author (FT from now on) thirty minutes

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Figure 3: Positioning of the camera among theother objects in the recording room.

earlier than their friends. During this interview, FTinformed the confederates that it was their respon-sibility to elicit natural speech from their friends,by raising appropriate topics whenever the conver-sation seemed to approach a dead end. In order tomaximize the amount of recorded speech from thespeakers, they were instructed not to monopolizethe conversation. They were also informed thatthe conversation would be filmed, and where to sitso that only the other participants would appear inthe film. Importantly, they were asked not to un-veil any of these details to their friends until theend of the recording, and to pretend that they hadnever met FT. Finally, they were briefly instructedabout the activity planned for the third part of therecording (see below for details).At the end of the interview, the confederates wereasked to wait for the other participants in the en-try hall. At the time of the appointment, FT metthe three participants there and asked them to waitwhile he made an urgent phone call. He then re-turned to the recording room, started the videorecording, turned off the lights and closed the door.Back at the entry hall, he invited the participantsto follow him to the recording room, making surethat the confederate would be the first person toenter in order to prevent the other participantsfrom taking her/his seat. Once in the room, theparticipants were asked to stay seated and not totouch their microphones or play with any other ob-ject (e.g. keys, watch) during the conversation.

Part 1: After adjusting the recording volume fromoutside the booth, FT entered the recording boothagain and informed the participants that the con-federate’s microphone was not working properly.He then asked the confederate to come out of theroom in order to try a new one. At this moment,the speakers left in the room did not know withcertainty whether they were being recorded. It wasprecisely then that the recording was started. Thissituation elicited very natural speech right fromthe beginning of the recording.Part 2: After a period of ten to thirty minutes (de-pending on the liveliness of the conversation), con-federates were asked to go back into the room.The conversation then held by the three partici-pants constituted the second part of the recordings.No instructions were provided about the topics tobe discussed during this part of the conversation.Among the conversation topics addressed by thespeakers during this part were exams, parties, andtravel plans. Words characteristic of such topicsare therefore well represented in this part of therecordings (e.g. 86 tokens of the word estudiar‘study’ and morphologically related words; 43 to-kens of the word viaje ‘travel’; 84 tokens of theword beber ‘to drink’ and morphologically relatedwords).Part 3: After a period of thirty to forty minutes,FT entered the room and provided the participantswith a sheet of paper describing the activity for theremaining part of the recording session. The par-ticipants were asked to choose at least five ques-tions about political and social issues from a list,and then negotiate a unique answer for every ques-tion. An English translation of this list can befound in Appendix A. In order to encourage theparticipants to negotiate common stances ratherthan just discuss the chosen topics, we informedthem that they would have to write down their an-swers at the end of the recording session. A char-acteristic of the speech elicited during this part isthat its vocabulary reflects the chosen questions.For instance, the word fumar ‘to smoke’ is veryfrequent in this part of the recordings (217 to-kens) because most groups of participants choseto discuss a question about a recent smoking banin Spain.At the end of the recording, we revealed our pro-cedures to the participants. We paid 30 euros to

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each of the speakers and 45 euros to the confed-erates as a compensation for their time. We thenhanded them a consent form agreeing to the use ofthe audio and video recordings for academic andscientific purposes. All of the participants signedthe consent form without adding any restriction.

3. Orthographic transcriptionThe corpus was orthographically transcribed inBarcelona by Verbio Speech Technologies S.L.using TRANSCRIBER software (Barras et al.,2001). The transcription process consisted ofthree passes. In the first pass, the speech of ev-ery pair of speakers was orthographically tran-scribed in a two-tier annotation file (one tier foreach speaker) from stereo-channel audio streams.Confederates, who had been recorded in a sepa-rate mono channel, were transcribed separately ina one-tier annotation file. The transcribed text isorganized into chunks, each containing not morethan 15 seconds of the speech signal. In the sec-ond pass, non-speech events (e.g. laughter, filledpauses, etc) were added to the orthographic tran-scription, the location of chunk boundaries wasreadjusted, and the spelling of the transcriptionwas checked on the basis of the Diccionario de laReal Academia Espanola (http://www.rae.es/rae.html). In the third pass, an automaticrevision of the formatting of the transcription fileswas performed. Every pass was carried out by adifferent transcriber.The orthographic transcription of the corpus con-tains around 393 000 word tokens and 16 500 wordtypes (distinct orthographic forms) distributedover 98 000 chunks. Part 1 contains around 83 000word tokens, while Parts 2 and 3 contain eacharound 155 000 word tokens.A look at the most frequent lexical items revealsthe casual and interactional nature of the corpus.For instance, speakers often used informal termsto address each other during the recordings (e.g.2750 tokens of tıo, 1789 tokens of tıa). Swearwords, which are not expected to occur in a for-mal setting, are also numerous (e.g. 822 tokens ofjoder, 245 tokens of puta). The interactional na-ture of the corpus is reflected among other thingsin the high frequency of discourse markers (e.g.3445 tokens of sabes, 2457 tokens of pues, 1744tokens of bueno).

4. Corpus availabilityInformation about how to obtain a copyof the corpus can be found online athttp://mirjamernestus.ruhosting.nl/Ernestus/NCCSp. This webpage alsoprovides audio and transcription examples, scriptsfor searching the corpus using Praat, and more in-formation about each participant and conversationin the corpus.

5. AcknowledgementsWe would like to thank Jose Manuel Pardo, JavierOrtega-Garcıa and Roberto Barra Chicote for theirhelp during the creation of this corpus.

6. ReferencesClaude Barras, Edouard Geoffrois, Zhibiao Wu,

and Mark Liberman. 2001. Transcriber: devel-opment and use of a tool for assisting speechcorpora production. Speech Communication,33(1-2):5–22.

Francisco Torreira, Martine Adda-Decker, andMirjam Ernestus. 2010. The Nijmegen Cor-pus of Casual French. Speech Communication,52:201–121.

A Activity sheet (English translation)SECOND PART

Now you will answer to at least five from the fol-lowing questions:

• What do you think about the smoking ban inpublic spaces?

• What do you think about the legalization ofsoft drugs?

• Why aren’t boys and girls raised in the sameway?

• Do you think that Al Gore deserved the PeaceNobel Prize?

• How would you improve the higher educa-tion system?

• Do you think that the housing situation willimprove or worsen in the future?

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• Did you approve the electoral campaign ofthe PSOE party?

• Did you approve the electoral campaign ofthe PP party?

• What team will win the football league thisseason?

• Is it possible to fight against urban corruptionin Spain?

For every question, you will try to negotiate a com-mon answer as well as you can. Once the record-ing has finished, one of you will write down yourcommon answers about each of the chosen ques-tions. You will therefore need to clearly determineyour common answers as well as any point forwhich an agreement was not possible.

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