Patent Publication Number: US-8112282-B2

Title: Evaluating prompt alternatives for speech-enabled applications

Description:
This application is a Continuation of application Ser. No. 11/834,520, filed Aug. 6, 2007, now U.S. Pat. No. 7,653,549 issued Jan. 26, 2010, which is a Divisional of application Ser. No. 11/363,456, filed Feb. 27, 2006, now abandoned, which is a Continuation of application Ser. No. 10/942,605, filed Sep. 16, 2004 now U.S. Pat. No. 7,043,435, issued May 9, 2006. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     The present invention relates generally to speech-enabled applications and, more particularly, to a system and method for optimizing prompts for speech-enabled applications. 
     BACKGROUND OF THE INVENTION 
     Developments in speech recognition technologies support more natural language interaction between services, systems and customers than previously supported. One of the most promising applications of speech recognition technology, Automatic Call Routing (ACR), seeks to determine why a customer has called a service center and to route the customer to an appropriate service agent for customer request servicing. Speech recognition technology generally allows an ACR application to recognize natural language statements from the customer, thus minimizing reliance on conventional menu systems. This permits a customer to state the purpose of their call “in their own words”. 
     In order for an ACR application to properly route calls, the ACR generally must interpret the intent of the customer, identify the type or category of customer call, and identify the correct routing destination for the call type. An ACR application may attempt to match one or more words in a statement by a customer to a particular pre-defined action to be taken by the ACR application. 
     Although speech recognition technology has been improving over the years, speech recognition systems are limited by the quality and robustness of the statistical language models or other techniques used to recognize speech. Given these limits, developers of these systems strive to develop prompts, announcements, and other instructions to the users of such systems that guide these users to provide speech input that conforms with the capabilities of the particular speech recognition technology used by the system. Subtle differences in the way prompts or other instructions are worded may result in substantial differences in system performance. 
     SUMMARY OF THE INVENTION 
     In accordance with a particular embodiment of the present invention, a computer-implemented method is provided for optimizing prompts for a speech-enabled application. The speech-enabled application is operable to receive communications from a number of users and communicate one or more prompts to each user to elicit a response from the user that indicates the purpose of the user&#39;s communication. The method includes determining a number of prompt alternatives (each including one or more prompts) to evaluate and determining an evaluation period for each prompt alternative. The method also includes automatically presenting each prompt alternative to users during the associated evaluation period and automatically recording the results of user responses to each prompt alternative. Furthermore, the method includes automatically analyzing the recorded results for each prompt alternative based on one or more performance criteria and automatically implementing one of the prompt alternatives based on the analysis of the recorded results. 
     Technical advantages of particular embodiments of the present invention include a method and system for optimizing prompts for speech-enabled applications that improve the operation of such applications. For example, particular embodiments automate the evaluation of various prompts or other user instructions for speech-enabled applications and then automatically implement the most effective prompt(s). Such embodiments can automatically present numerous prompt variations to users, evaluate the impact of each prompt on some measure of system performance, and adopt the prompt(s) that lead to the best system performance. This automation of prompt evaluation and implementation can reduce development time and ensure high system performance. 
     Other technical advantages will be readily apparent to one skilled in the art from the following figures, descriptions and claims. Moreover, while specific advantages have been enumerated above, various embodiments may include all, some or none of the enumerated advantages. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the present embodiments and advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features, and wherein: 
         FIG. 1  is a block diagram depicting an example embodiment of a service center system according to one embodiment of the present invention; 
         FIG. 2  is a flow diagram depicting an example automatic call routing method according to one embodiment of the present invention; 
         FIG. 3  is a diagram depicting an example embodiment of an automatic call router action-object matrix according to one embodiment of the present invention; and 
         FIG. 4  is a flow diagram depicting an example method for optimizing prompts for speech-enabled applications according to one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a block diagram depicting an example embodiment of a service center system  100  according to one embodiment of the present invention. System  100  enables users to conduct transactions via a service center  102 . For example, as referred to herein, service center  102  may be a customer service call center for a telephone services company. However, as described below, the present invention may be used in conjunction with any other types of call centers, as well as with any systems that use speech recognition to perform an action or otherwise facilitate an action in response to speech input of a user. As used herein, the term “transaction” or it variants refers to any action that a user desires to perform in conjunction with or have performed by service center  102 . 
     The example service center  102  includes one or more computing apparatuses  104  that are operably coupled to one or more transaction processing service solutions  106 . Included in computing apparatus  104  is a processor  108 . Operably coupled to processor  108  of computing apparatus  104  is a memory  110 . Computing apparatus  104  employs processor  108  and memory  110  to execute and store, respectively, one or more instructions of a program of instructions (i.e., software). 
     Also included in computing apparatus  104  is communication interface  112 . Communication interface  112  is preferably operable to couple computing apparatus  104  and/or service center  102  to an internal and/or external communication network  114 . Communication network  114  may be the public-switched telephone network (PSTN), a cable network, an internet protocol (IP) network, a wireless network, a hybrid cable/PSTN network, a hybrid IP/PSTN network, a hybrid wireless/PSTN network, the Internet, and/or any other suitable communication network or combination of communication networks. 
     Communication interface  112  preferably cooperates with communication network  114  and one or more user communication devices  116  to permit a user associated with each user communication device  116  to conduct transactions via service center  102 . User communication device  116  may be a wireless or wireline telephone, dial-up modem, cable modem, DSL modem, phone sets, fax equipment, answering machines, set-top boxes, televisions, POS (point-of-sale) equipment, PBX (private branch exchange) systems, personal computers, laptop computers, personal digital assistants (PDAs), other nascent technologies, or any other appropriate type or combination of communication equipment available to a user. Communication device  116  may be equipped for connectivity to communication network  114  via a PSTN, DSL, cable network, wireless network, or any other appropriate communications channel. 
     In operation, service center  102  permits a user to request, using speech, processing or performance of one or more transactions by service solutions  106 . To enable such processing, computing apparatus  104  may include or have access to one or more storage devices  118  including one or more programs of instructions operable to interpret user intent from the user&#39;s speech, identify a solution sought by the user, and route the user to an appropriate service solution  106 . 
     To aid in the interpretation, identification and routing operations of service center  102 , storage  118  includes an action-object matrix  120 , a look-up table  122 , utterance storage  124 , a prompt library  126 , one or more speech recognition modules (such as a statistical language modeling engine  128 ), and one or more dialog modules  129 . Furthermore, to analyze and optimize the performance of the prompts used by service center  102 , storage  118  also includes a prompt test control module  144  and a prompt test analysis module  146 . Additional details regarding the operation and cooperation of the various components included in storage  118  will be discussed in greater detail below. 
     In the illustrated embodiment, computing apparatus  104  is communicatively coupled to one or more connection switches or redirect devices  130 . Connection switch or redirect device  130  enables computing apparatus  104 , upon determining an appropriate destination for the processing of a user-selected transaction, to route the user via communication network  132  and, optionally, one or more switches  134 , to an appropriate service agent or module of service solutions  106 . 
     Service solutions  106  preferably include a plurality of service agents or modules operable to perform one or more operations in association with the processing of a selected user transaction. For example, if service center  102  is a telephone services call center, service solutions  106  may include one or more service agents or modules operable to perform billing service solutions  136 , repair service solutions  138 , options service solutions  140 , how-to-use service solutions  142 , as well as any other appropriate service solutions. The service agents or modules implemented in or associated with service solutions  106  may include, but are not limited to, automated or self-service data processing apparatuses, live technician support (human support), or combinations thereof. 
       FIG. 2  illustrates an example method  150  for a speech-enabled call routing using an action-object matrix according to one embodiment of the present invention. However, it should be emphasized that embodiments of the present invention may be used in association with any speech-enabled applications using prompts and is certainly not limited to service centers routing users using action-objects. Method  150  of  FIG. 2  may be implemented in one or more computing apparatuses  104  of one or more service centers  102 . As such the method will be described with reference to the operation of service center  102  of  FIG. 1 . 
     Upon initialization of service center  102  at step  152 , method  150  proceeds to step  154  where service center  102  provides for and awaits an incoming communication from a user communication device  116  via communication network  114 . However, a user may connect with service center  102  in any other suitable manner. 
     Upon detection of an incoming contact at step  154 , method  150  preferably proceeds to step  156  where a communication connection with the user communication device  116  is established. As suggested above, establishing a communication connection with an incoming contact from a user at step  156  may include, but is not limited to, receiving a user phone call via a PSTN or other wireline network, a wireless network, or any of numerous other communication networks. 
     Once a communication connection has been established at step  156 , method  150  proceeds to step  158  where one or more prompts, announcements, or other instructions to the user (collectively referred to herein as “prompts”) are communicated to the user of user communication device  116 . In particular embodiments, the communication of one or more prompts is aimed at eliciting a request from the user for the processing of one or more transactions or operations. For example, at step  158 , dialog module  129  may access prompt library  126  of storage  118  to generate a user transaction selection prompt such as, “Thank you for calling our service center. Please tell me how we may help you today.” Furthermore, any other suitable prompts designed to elicit a response from the user regarding a transaction that the user desires to be performed may be used. 
     Preferably, a prompt will serve to elicit an unambiguous statement of the user&#39;s intent. If the user utterance is ambiguous or incomplete service center  102  will need to engage in additional dialog to clarify the user&#39;s intentions. For example, in response to initial prompt from service center  102 , the most desirable outcome is for the user&#39;s response to the prompt to result in a “direct route” to the appropriate destination. However, if the user&#39;s response requires additional clarification (further user responses) before service center  102  can determine the appropriate destination, service center  102  will need to employ dialog module  129  to provide additional prompts to the user in an attempt to elicit an unambiguous statement from the user. This additional prompting increases costs (for example, by occupying incoming communication channels) and reduces customer satisfaction. 
     At step  160  of method  150 , service center  102  awaits a user response to the communicated prompt. Upon detection of a user response at step  160 , method  150  preferably proceeds to  162  where a natural language response (a user “utterance”) from the user responsive to the communicated prompt is preferably received. Receipt of an utterance from a user may include storage of the user&#39;s utterance in utterance storage  124  of computing apparatus storage  118 . Permanent or temporary storage of a user utterance may enable and/or simplify the performance of speech recognition analysis thereon. 
     Following receipt of a user utterance at step  162 , method  150  proceeds to step  164  where the user utterance is evaluated to interpret or identify an intent of the user and a requested transaction to be performed. In particular embodiments, evaluation of a user utterance at step  164  may include the use of one or more speech recognition technologies, such as that available from statistical language modeling engine  128  of computing apparatus  104 . As suggested above, statistical language modeling engine  128  may cooperate with utterance storage  124  in the evaluation of the user utterance. 
     In certain embodiments, statistical language modeling engine  128  may evaluate the user utterance received at step  162  in cooperation with action-object matrix  120 , which defines a number of different action-objects (and which is described in greater detail below in conjunction with  FIG. 3 ). In the evaluation of a user utterance at step  164 , the speech recognition technology preferably employed by computing apparatus  104  seeks to identify an action, an object or an action-object combination from the user utterance. By creating a finite number of transaction options (i.e., action-objects) via action-object matrix  120 , proper routing of a user to a service agent or module  136 ,  138 ,  140  or  142 , may be accomplished with improved efficiency (for example, substantially eliminating user routing errors and, therefore, user re-routing). 
     Each action-object in action-object matrix  120  defines a particular action to be taken and an object that is the subject of the action (in other words, a transaction to be performed). For example, the action-object “pay/bill” defines an action “pay” to be carried out on an object “bill.” As described below, the assignment of an action-object to a user utterance enables efficient routing of the user to enable performance of a desired transaction. 
     To assist in assigning a particular action-object to a user utterance in particular embodiments, statistical language modeling engine  128  may store and associate one or more salient action terms and one or more salient object terms with each action-object. The statistical language modeling engine  128  can then search for these salient terms in a user utterance to assign the user utterance to a particular action-object. The salient terms may be the actual action and object of the action-object and/or the salient terms may be different from the action and object. For example, the action-object “pay/bill” may be associated with the salient action term “pay” and the salient object term “bill.” In addition, the “pay/bill” action-object may be associated with the salient object terms “account” and “invoice.” Therefore, any user utterance including the term “pay” and at least one of the terms “bill,” “account” or “invoice” would preferably be associated with the “pay/bill” action-object. Multiple salient action terms could also or alternatively be associated with this action-object. At least a portion of the user utterance evaluation performed at step  164  may include determining whether the user utterance includes a salient action term, a salient object term, or both a salient action term and a salient object term. 
     If it is determined that the user utterance contains only a salient action term(s)  168 , method  150  proceeds to step  176  where one or more additional prompts may be communicated to the user using dialog module  129 , using a different dialog module  129  than the module that communicated the initial prompt, or using any other suitable component. The prompts presented at step  176  are preferably designed to elicit the selection of an object (via a salient object term) in a subsequent user utterance. For example, referring to the action-object matrix depicted in  FIG. 3 , it may have been determined from the initial user utterance that the user desires to “inquire” about something. Having identified that the user wishes to make an “inquiry” (the action), computing apparatus  104  may cooperate with dialog module  129 , prompt library  126  and action-object matrix  120  to prompt the user for selection of an object associated with the “inquire” action. As illustrated in  FIG. 3 , examples of objects associated with the “inquire” action include, in one embodiment, optional services, basic service, billing, cancellation, repair, payment, specials, and name and number. It should be understood that the action-object matrix depicted generally in  FIG. 3  is included primarily for purposes of illustration. As such, alternate embodiments of an action-object matrix (or embodiments not using an action-object matrix) may be implemented without departing from the spirit and scope of teachings of the present invention. 
     Similarly, if it is determined that the user utterance contains only a salient object term  170 , method  150  preferably proceeds to step  178  where one or more prompts designed to elicit the selection of an action (via a salient action term) in a subsequent user utterance. For example, referring again to the action-object matrix generally depicted in  FIG. 3 , if it is determined from the initial user utterance that the user desires some sort of action associated with a “bill”, computing apparatus  104  may cooperate with dialog module  129 , action-object matrix  120  and prompt library  126  to generate one or more prompts directed to eliciting user selection of an “action” associated with the bill “object”. As shown in  FIG. 3 , examples of actions associated with a “bill” object may include, in one embodiment, inquiry, information, fixing or repairing, and paying. 
     Method  150  may loop through steps  176  or  178  one or more times in an attempt to elicit an appropriate salient action term or an appropriate salient object term, respectively, for any desired number of loops. If evaluation of the user utterances does not lead to the utterance of a salient action term  168  nor a salient object term  170  after a predetermined number of loops, if neither a salient action term  168  or a salient object term  170  are identified (an “other” utterance  174 ), or if salient action terms  168  and/or salient object terms  170  associated with multiple action-objects are identified, then method  150  proceeds to step  180  where a disambiguation dialogue may be initiated and performed by dialog module  129 . In such an event, method  150  preferably provides for additional appropriate dialogue to be performed with the user in an effort to elicit a usable “action-object” combination from the user (for example, asking the user to be more specific in his or her request). 
     Following prompting for an “object” at step  176 , prompting for an “action” at step  178 , or initiation and performance of disambiguation dialogue at  180 , method  150  preferably returns to step  160  where a response may be awaited as described above. Method  150  then preferably proceeds through the operations at steps  162  and  164  until an “action-object” combination  172  has been elicited from the user in a user utterance. An escape sequence may also be included in method  150  where it has been determined that a user requires human assistance, for example. 
     After identification of an “action-object” combination  172  (either from the initial utterance or from the repeated prompting described above), method  150  preferably proceeds to step  182 . At step  182 , computing apparatus  104  preferably cooperates with action-object matrix  120  and look-up table  122  to identify a preferred or proper routing destination for processing the user-selected transaction. As suggested above, the routing destinations identified at step  182  may include routing destinations associated with the service agents or modules available in service solutions  106 . As mentioned above, service agents or modules  136 ,  138 ,  140  and  142  may include automated transaction processing available via computing apparatus  104  or a similar device, live support, or combinations thereof, as well as other suitable transaction processing options. 
     Following identification of a preferred or proper routing destination at step  182 , method  150  preferably proceeds to step  184  where the user connection is preferably routed to the appropriate destination indicated in look-up table  122 . Following the routing of the user connection, method  150  preferably proceeds to step  186  where one or more aspects of the user utterance or utterances are optionally forwarded to the service agent or module destination to which the caller and/or user connection is routed. For example, in particular embodiments, method  150  provides for the identified action-object to be forwarded to the service agent associated with the selected routing destination. In yet other embodiments, no information is forwarded and the user is simply routed to the appropriate destination. Following the routing of the user connection (and any forwarding of information), method  150  preferably returns to step  154  where another user connection is awaited. 
     It should be understood that some of the steps illustrated in  FIG. 2  may be combined, modified or deleted where appropriate, and additional steps may also be added to the method. Additionally, as indicated above, the steps may be performed in any suitable order without departing from the scope of the present invention. Furthermore, it should be understood that although embodiments of the present invention are described in conjunction with a service center using action-objects and salient terms, the present invention may be used in conjunction with any speech-enabled applications that use prompts to elicit a response to determine the user&#39;s intent. 
     Referring again to  FIG. 3 , an action-object matrix  120  according to one embodiment of the present invention is shown. The example action-object matrix  120  shown in  FIG. 3  includes a number of columns of actions  202  and a number of rows of objects  204 . The intersection of an action column with an object row generally defines an action-object pair identifying a transaction available via service center  102  (for example, using one or more service modules or agents  136 ,  138 ,  140  and  142 ). 
     As described above, action-object matrix  120  is used in association with other components of service center  102  to interpret user intent and identify a desired transaction from a user utterance. For example, using actions  202  and objects  204  of action-object matrix  120 , in conjunction with the method  150  described above, a user utterance such as “How much do I owe on my bill?” may be evaluated to relate to the action-object “inquire/bill”  206 . In a further example, the user utterance, “I have a problem with a charge on my bill” may be associated with the action-object “fix-repair/bill”  208 . In still another example, the user utterance, “Where can I go to pay my phone bill?” may be associated with the action-object “where/payment”  210 . In yet another example, the user utterance, “How do I set up Call Forwarding?” may be associated with the action-object “how-to-use/option” services  212 . In a further example, the user utterance, “I&#39;d like to get CallNotes” may be associated with the action-object “acquire/optional services”  214 . 
     As mentioned above, service center  102  uses one or more salient action terms and one or more salient object terms associated with each action-object to associate a user utterance with the action-object. The salient terms may be stored in association with action-object matrix  120  or elsewhere in service center  102  (or at a location remote to service center  102 ). If stored in association with action-object matrix  120 , the salient terms may be linked to particular action-objects, to particular actions (for salient action terms), or to particular objects (for salient object terms). 
     After an action-object has been identified through the user of action-object matrix  120  and other components of service center  102 , look-up table  122  is used to identify the routing destination associated with an identified action-object. For example, upon identifying action-object “inquire/bill”  206  from a user utterance, computing apparatus  104  may utilize action-object matrix  120  and look-up table  122  to determine that the appropriate routing destination for the “inquire/bill” action-object  206  is “Bill” service agent or module  136 . In another example, upon identifying action-object “fix-repair/bill”  208  from a user utterance, computing apparatus  104  cooperating with action-object matrix storage  120  and look-up table  122  may determine that an appropriate routing destination for the user connection includes “Repair” service agent or module  138 . Additional implementations of associating a look-up table with an action-object matrix may be utilized without departing from the spirit and scope of teachings of the present invention. 
       FIG. 4  is a flow diagram depicting an example method  300  for optimizing prompts for speech-enabled applications according to one embodiment of the present invention. As described above, although the example method  300  is described with respect to service center  102 , the method may be applied to any speech-enabled application that uses prompts (again, this term refers to prompts, announcements, or any other instructions provided to a user) to elicit a response to determine a user&#39;s intent (regardless of how the user&#39;s intent is determined). 
     Upon initialization at step  302 , method  300  proceeds to step  304  where a particular dialog module  129  to evaluate is selected. A speech-enabled application, such as service center  102 , may include multiple dialog modules  129  and each dialog module may be tested separately. For example, an application may have one dialog module  129  that provides the initial prompt (and any associated announcements) and may include other dialog modules that provide additional prompts to obtain more detailed or unambiguous responses from a user. Using service center  102  as an example, control of the prompt testing process may be performed by test control module  144  and thus module  144  may select a dialog module to evaluate. If service center  102  includes multiple dialog modules  129 , test control module  144  may serially select each dialog module  129  for testing at particular intervals. This selection may be performed automatically based on a pre-determined configuration or may be based on input from a person configuring the test procedure. 
     Method  300  continues at step  306  where the prompt alternatives to evaluate for the selected dialog module are determined. For example, prompt library  126  may include multiple alternative prompts for the initial prompt provided by service center  102 . Test control module  144  may access prompt library  126  to retrieve these alternative prompts and may determine which prompts are to be evaluated. For example, prompt library  126  may initially include several alternative initial prompts and test control module  144  may initially select all the alternative prompts for testing. As an example, after testing all of the alternative initial prompts, test control module  144  may eliminate certain prompts that performed poorly relative to the other prompts and may repeat the testing process on the remaining prompts if necessary. Alternatively, the particular prompts to be evaluated may be determined based on input from a person configuring the test procedure. 
     In some cases, one or more of the prompt alternatives may include a combination of prompts (including announcements, etc.) to be evaluated. For example, method  300  could be used to test an announcement followed by a prompt or a series of prompts. Therefore, at step  308  it is determined whether prompt combinations are being evaluated. If so, method  300  continues to step  310  where the order and particular combinations of the prompts to be tested are determined. For example, the same initial prompt could be tested with three different preceding announcements, or an announcement could be tested with three different prompts following the announcement. As another example, an initial prompt could be followed by pauses of different lengths (or no pause) before a series of example responses are provided to the user. As yet another example, the order of two or more prompts may be tested, with each different order being a different alternative. Any particular combination and/or order of prompts may be tested. Furthermore, other variations of the way in which multiple prompts are played may be evaluated. The information regarding the different combinations to be tested may be provided to and stored by test control module  144  for use in executing the testing. 
     Once the order the prompts in each of the prompt alternatives has been determined (or if it is determined at step  308  that the prompt alternatives do not include any prompt combinations), method  300  proceeds to step  312  where the number of prompt cycles, length of time, and/or other characteristics of the evaluation period during which each prompt alternative is to be evaluated is determined. For example, a first prompt alternative “How may I help you?” may be used as the initial prompt for a one week period and then a second prompt alternative “What is the purpose of your call?” may be used for the following one week period. Alternatively, as an example, the first prompt alternative may be tested for the first one thousand prompt cycles (for example, calls from users) and the second prompt alternative may be tested for the next thousand prompt cycles. Furthermore, prompt alternatives may be testing in an alternating fashion (for example, a first prompt may tested for a single user, a second prompt may be tested on the next user, and the process may be repeated any desired number of times). Moreover, one or more of the alternative prompts may be tested for differing lengths of times, number of prompt cycles, or other evaluation periods as desired. Information about the testing period(s) to be used for each prompt alternative may be provided to and stored by test control module  144  for use in executing the testing. 
     Method  300  continues at step  314 , where a first prompt alternative is selected from the multiple prompt alternatives determined to be part of the evaluation at step  306 . This step may be performed automatically by test control module  144 . For example, if the two prompt alternatives to be evaluated are “How may I help you?” and “What is the purpose of your call?”, then test control module  144  may select one of these alternatives to begin testing. 
     At step  316 , the selected prompt alternative is retrieved from prompt library  126  (or any other suitable location). For example, the prompt alternative may be an audio file (such as a .wav file) that is retrieved from prompt library  126 ). At step  318 , the retrieved prompt alternative is presented to a user. For example, a .wav file may be played for the user. The playing or other presentation of the prompt alternative (which, again, may include a combination of prompts, announcements, pauses, etc.) is repeated for each user (such as callers calling into service center  102 ) during the evaluation period determined at step  312 . The selected prompt may be retrieved and presented by the associated dialog module  129 , test control module  144 , or any combination thereof (and reference to dialog module  129  performing this task is meant to include any of these options). 
     At step  320 , test analysis module  146  or any other suitable component (such as test control module  144 ) records the results of each user&#39;s actions taken in response to the prompt alternative. Any suitable results of the user&#39;s interaction with service center  102  or other application presenting a prompt can be recorded for later evaluation. For example, the user&#39;s actual response(s) to the prompt alternatives may be recorded. In addition or alternatively, whether the user&#39;s response included a salient action term and/or a salient object term (for example, based on an evaluation of the response by statistical language modeling engine  128 ) may be recorded. As another example, test analysis module  146  or another suitable component may record whether the user&#39;s response resulted in a direct route or whether it required additional dialog from a dialog module  129  to clarify the user&#39;s intent. The component, such as test analysis module  146 , recording this information for evaluation can cooperate with any other suitable components of the system being analyzed to obtain this information. For example, test analysis module  146  may communicate with statistical language modeling engine  128 , action-object matrix  120 , dialog module(s)  129 , or any other appropriate components of service center  102  to record suitable information for evaluating the performance of a particular prompt alternative. 
     Furthermore, it is again emphasized that the present invention may apply to any type of speech-enabled applications, and is not limited to the service center example provided herein. Therefore, suitable performance criteria may be unrelated to the routing of users/callers to a destination. For a given prompt, or set of prompts, a variety of performance measures may be evaluated, such as the percentage of timeouts (for example, when no response is received from a user), the percentage of “too much speech” (for example, the user says more than the speech engine can process), the percentage of utterances that are “in grammar” (for example, the utterance matches a defined grammar item in an engine that recognizes types of grammar), or the number of times a caller asks for “help.” These are but a few examples and there are a wide range of different measures for prompt performance other than action-objects and direct routes. 
     At the end of the evaluation period for the first prompt alternative, method  300  proceeds to step  322  where it is determined whether there are additional prompt alternatives to evaluate. For example, test control module  144  can determine whether all the prompt alternatives selected at step  306  have been evaluated. If there are additional prompt alternatives to evaluate, method  300  returns to step  314 , where the next prompt alternative to evaluate is selected. Steps  316  through  320  are then performed for that prompt alternatives, as described above. 
     Once it is determined at step  322  that no further prompt alternatives remain to be evaluated (for the selected dialog module), method  300  proceeds to step  324  where test analysis module  146  or any other suitable component analyzes the information recorded at step  320  for each of the prompt alternatives. For example, test analysis module  146  may determine which prompt alternative resulted in the most direct routes (for example, the highest percentage of direct routes) or which alternative had the most initial responses that resulted in a match with an action-object (for example, responses that included both a salient action term and a salient object term). Any number of additional or alternative performance criteria that assist in identifying the most effective prompt alternative may be analyzed by analysis module  146 , as desired. This analysis may be performed in “real-time” while service center  102  or other system being evaluated is continuing to interact with users. Furthermore, some or all of analysis step  324  may occur for each prompt alternative while that prompt alternative or other prompt alternatives are being tested. 
     Based on the analysis performed at step  324 , test analysis module  146  compares the results of the analysis and determines the “best” prompt alternative at step  326 . Which prompt alternative is the best depends on the criteria being evaluated. As examples only, the prompt alternative resulting in the most direct routes or resulting in the most action-object matches (either initially or after further prompting) may be selected as the best prompt alternative at step  326 . Once the best prompt alternative is selected, test analysis module  146  or any other suitable component automatically adjusts the dialog module at step  328  to implement the chosen prompt alternative. This automatic evaluation and adjustment of prompts is advantageous since manually testing and adjusting various prompts is time consuming and may interrupt or impede the performance of the system being tested. 
     After the dialog module  129  being tested is appropriately adjusted, method  300  continues to step  330  where it is determined whether there are additional dialog modules  129  to evaluate. If so, method  300  returns to step  304  where a new dialog module  129  is selected for evaluation. If not, method  300  ends. Method  300  may be repeated as often as desired during the operation of a service center or other speech-enabled application to which the method might apply. For example, method  300  may be performed when a service center or other speech-enabled application is initially put into operation. Thereafter, the method could be performed periodically as desired (for example, every six months). Such periodic testing may be helpful as users become experienced with the prompts used in a system. The users&#39; behavior can change with such experience and periodic updating of the prompts can be beneficial to “tune” the prompts to take into account the users&#39; changed behavior. 
     It should be understood that some of the steps illustrated in  FIG. 4  may be combined, modified or deleted where appropriate, and additional steps may also be added to the method. Additionally, as indicated above, the steps may be performed in any suitable order without departing from the scope of the present invention. 
     Although the present invention has been described in detail with reference to particular embodiments, it should be understood that various other changes, substitutions, and alterations may be made hereto without departing from the spirit and scope of the present invention. For example, although the present invention has been described with reference to a number of components included within service center  102 , other and different components may be utilized to accommodate particular needs. The present invention contemplates great flexibility in the arrangement of these elements as well as their internal components. Moreover, speech-enabled applications or systems other than service centers may also be used in conjunction with embodiments of the present invention. 
     Furthermore, numerous other changes, substitutions, variations, alterations and modifications may be ascertained by those skilled in the art and it is intended that the present invention encompass all such changes, substitutions, variations, alterations and modifications as falling within the spirit and scope of the appended claims. Moreover, the present invention is not intended to be limited in any way by any statement in the specification that is not otherwise reflected in the claims.